Complication vs Difficulty vs Issue vs Obstacle vs Problem

When to use each in English, with meaning, register, and examples.

Complication

Top 2,000 (common)C1noun

Difficulty

Top 2,000 (common)B1noun

Issue

Top 1,000 (very common)B1noun

Obstacle

Top 2,000 (common)B2noun

Problem

Top 1,000 (very common)A1noun
 ComplicationDifficultyIssueObstacleProblem
Pronunciation🇬🇧 /["/ˌkɒmplɪˈkeɪʃn/"]/🇺🇸 /["/ˌkɑːmplɪˈkeɪʃn/"]/🇬🇧 /["/ˈdɪfɪkəlti/"]/🇺🇸 /["/ˈdɪfɪkəlti/"]/🇬🇧 /["/ˈɪʃuː/"]/🇺🇸 /["/ˈɪʃuː/"]/🇬🇧 //ˈɒbstəkl//🇺🇸 //ˈɑbstəkl//🇬🇧 /["/ˈprɒbləm/"]/🇺🇸 /["/ˈprɑːbləm/"]/
MeaningA problem or difficulty that makes something harder.How hard something is.A problem or topic that people discuss.Something that makes it difficult to do something.A difficulty or issue that needs to be solved.
ExampleThe surgeon explained that there could be a complication during the procedure.The difficulty of the exam surprised many students.The main issue we need to address is the lack of communication.He faced many obstacles during his journey to success.Math can be hard, but I will solve this problem.
RegisterNeutralNeutralNeutralNeutralNeutral
How commonTop 2,000 (common)Top 2,000 (common)Top 1,000 (very common)Top 2,000 (common)Top 1,000 (very common)
CEFR levelC1B1B1B2A1
Part of speechnounnounnounnounnoun
Collocationsmajor, added, additional, add, cause, avoid, arise, ensue, occur, acute, dangerous, life-threatening, develop, have, suffer, arise, develop, occur, rate, complication with, complication from, complication of, a risk of complications, complications related to somethingconsiderable, enormous, extreme, level, encounter, experience, face, arise, lie (in something), despite a/​the difficulty, in difficulty, with difficulty, considerable, enormous, extreme, level, encounter, experience, face, arise, lie (in something), despite a/​the difficulty, in difficulty, with difficulty, considerable, enormous, extreme, level, encounter, experience, face, arise, lie (in something), despite a/​the difficulty, in difficulty, with difficultybig, burning, central, number, range, series, raise, debate, discuss, arise, surround something, underlie something, at issue, on an/​the issue, issue about, make an issue of something, big, burning, central, number, range, series, raise, debate, discuss, arise, surround something, underlie something, at issue, on an/​the issue, issue about, make an issue of something, current, back, special, bring out, publish, come out, go on sale, be out, in an/​the issueface an obstacle, overcome an obstacle, see an obstacleacute, big, enormous, host, set, be, pose, present (somebody with), arise, come up, crop up, area, spot, behaviour/​behavior, problem about, problem for, problem of, an approach to a problem, the crux of the problem, the heart of the problem, complicated, difficult, easy, do, find the answer to, solve, set
Antonymssolution, simplicity, resolutioneasy, simple, effortlesssolution, answeradvantage, help, facilitatorsolution, answer, resolution
Common mistakesConfused with 'complicating' which implies making something difficult., Using 'complication' in contexts unrelated to problems, like 'easy' situations.Confused with 'difficult' (adjective) vs. 'difficulty' (noun), Using 'difficulties' when referring to multiple challenges, Overgeneralizing to describe feelings instead of tasks'Issue' confused with 'problem' when referring to minor matters that don't require attention., Using 'issue' without a clear context, making it sound vague or unclear., Overusing 'issue' in informal settings, where a simpler term might be more appropriate.Confusing with 'obstacle course' which is a specific kind of challenge., Using 'obstacles' when discussing non-physical challenges like fears or emotions., Mixing it up with 'obstruction', which often has legal connotations.'Problem' is often confused with 'trouble'—these words have slightly different meanings., Some learners may use 'problems' incorrectly with uncountable nouns., Use the phrase 'to solve a problem' instead of 'to fix a problem'.
Usage notesUse 'complication' when discussing medical issues or difficulties in plans. Avoid in casual conversations unless talking about serious matters.Often used to describe challenges in tasks, tests, or activities. Suitable in both casual and academic contexts. Avoid using in overly informal situations.Use 'issue' in discussions or formal settings to refer to problems or topics. Avoid using it in very casual conversations where simpler words like 'problem' might fit better.Used in contexts where something hinders progress or achievement. Typically neutral; avoid in overly casual contexts.Use 'problem' in both formal and informal contexts. Avoid using in overly casual situations when a lighter term might fit, like 'issue' or 'challenge'.

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Complication
Difficulty
Issue

Frequently asked questions: Complication vs Difficulty vs Issue vs Obstacle vs Problem

What's the difference between Complication, Difficulty, Issue, Obstacle, and Problem?

Complication: A problem or difficulty that makes something harder. Difficulty: How hard something is. Issue: A problem or topic that people discuss. Obstacle: Something that makes it difficult to do something. Problem: A difficulty or issue that needs to be solved.

Which is more advanced: Complication, Difficulty, Issue, Obstacle, and Problem?

Complication is the highest level, at C1, on the CEFR scale.

Are Complication, Difficulty, Issue, Obstacle, and Problem the same CEFR level?

Complication: C1, Difficulty: B1, Issue: B1, Obstacle: B2, Problem: A1 on the CEFR scale.

What part of speech are Complication, Difficulty, Issue, Obstacle, and Problem?

Complication: noun, Difficulty: noun, Issue: noun, Obstacle: noun, Problem: noun.

Can you show an example of each?

Complication: The surgeon explained that there could be a complication during the procedure. Difficulty: The difficulty of the exam surprised many students. Issue: The main issue we need to address is the lack of communication. Obstacle: He faced many obstacles during his journey to success. Problem: Math can be hard, but I will solve this problem.

Can I use Complication, Difficulty, Issue, Obstacle, and Problem interchangeably?

Not always. Complication, Difficulty, Issue, Obstacle, and Problem are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.