Complete vs Fill

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

Complete

Top 1,000 (very common)A1adjective

Fill

Top 1,000 (very common)A1verb
 CompleteFill
Pronunciation🇬🇧 /["/kəmˈpliːt/"]/🇺🇸 /["/kəmˈpliːt/"]/🇬🇧 /["/fɪl/","/fɪlz/","/fɪld/","/ˈfɪlɪŋ/"]/🇺🇸 /["/fɪl/","/fɪlz/","/fɪld/","/ˈfɪlɪŋ/"]/
MeaningTo finish something completely.To make something full by putting something inside it.
ExampleThe puzzle is now complete after I found the last piece.Please fill the glass with water.
RegisterNeutralNeutral
How commonTop 1,000 (very common)Top 1,000 (very common)
CEFR levelA1A1
Part of speechadjectiveverb
Collocationsbe, seem, survive, remarkably, very, far from, be, seem, almost, nearly, substantiallyfast, quickly, rapidly, begin to, seem to, with, be filled to capacity, be filled to the brim (with something)
Antonymsincomplete, unfinished, partialempty, drain, remove
Common mistakesConfused with 'finished' — both mean to end, but 'complete' emphasizes fullness., Using 'complete' when a task is partially done., 'Complete' is sometimes incorrectly used as a noun.Confusing 'fill' with 'fulfill' in contexts of completion., Using 'filled' instead of 'fill' in present tense statements., Mixing up the order of words, like saying 'to fill it with water' instead of 'fill it with water'.
Usage notesUse 'complete' in academic or professional contexts when discussing tasks, projects, or forms. Avoid using it in overly casual conversations.Use 'fill' when talking about putting substance into an empty space. It's common in both casual and formal contexts. Avoid using for emotional or abstract concepts, as it can lead to confusion.

Frequently asked questions: Complete vs Fill

What's the difference between Complete and Fill?

Complete: To finish something completely. Fill: To make something full by putting something inside it.

Are Complete and Fill the same CEFR level?

Complete: A1, Fill: A1 on the CEFR scale.

Can I use Complete and Fill interchangeably?

Not always. Complete and Fill 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.

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