Incur vs Sustain

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

Incur

Top 3,000 (common) C1 verb

Sustain

Top 2,000 (common) C1 verb

Most common: Sustain

	Incur	Sustain
Pronunciation	🇬🇧 /["/ɪnˈkɜː(r)/","/ɪnˈkɜːz/","/ɪnˈkɜːd/","/ɪnˈkɜːrɪŋ/"]/ 🇺🇸 /["/ɪnˈkɜːr/","/ɪnˈkɜːrz/","/ɪnˈkɜːrd/","/ɪnˈkɜːrɪŋ/"]/	🇬🇧 /["/səˈsteɪn/","/səˈsteɪnz/","/səˈsteɪnd/","/səˈsteɪnɪŋ/"]/ 🇺🇸 /["/səˈsteɪn/","/səˈsteɪnz/","/səˈsteɪnd/","/səˈsteɪnɪŋ/"]/
Meaning	To cause something to happen to yourself, usually something bad like a cost or penalty.	To keep something going or maintain it.
Example	She had incurred the wrath of her father by marrying without his consent.	We must find ways to sustain our natural resources for the future.
Register	Neutral	Neutral
How common	Top 3,000 (common)	Top 2,000 (common)
CEFR level	C1	C1
Part of speech	verb	verb
Collocations	incur costs, incur debt, incur risk, incur penalties, incur expenses	no longer, barely, indefinitely, be able to, can, be unable to
Antonyms	avoid, prevent	neglect, abandon, cease
Common mistakes	Using 'incur' without an object, e.g., 'I incur.', Confusing 'incur' with 'occur.', Not using it in the correct context, such as using in casual conversation.	'Sustain' is often confused with 'sustained' as a past form., Learners sometimes forget to add an object after 'sustain'., 'Sustain' is misused when referring to temporary situations, instead of ongoing support.
Usage notes	Used mostly in formal contexts such as finance or legal matters. Avoid using in casual conversation.	Use 'sustain' in contexts about keeping something alive or supporting it over time. It can be formal when discussing topics like environmental issues or less formal in conversations about personal interests.

See it in real clips

"And I might share with you some words which have sustained me

Sherlock › S1 E1

Impossible to sustain a smoking habit in London these days.

There's not a planet in our solar system that could sustain life...

"And I might share with you some words which have sustained me

Sherlock › S1 E1

Impossible to sustain a smoking habit in London these days.

Sustain

Frequently asked questions: Incur vs Sustain

What's the difference between Incur and Sustain?

Incur: To cause something to happen to yourself, usually something bad like a cost or penalty. Sustain: To keep something going or maintain it.

Which is more common: Incur and Sustain?

Sustain is the most common in everyday English.

Are Incur and Sustain the same CEFR level?

Incur: C1, Sustain: C1 on the CEFR scale.

What part of speech are Incur and Sustain?

Incur: verb, Sustain: verb.

Can you show an example of each?

Incur: She had incurred the wrath of her father by marrying without his consent. Sustain: We must find ways to sustain our natural resources for the future.

Can I use Incur and Sustain interchangeably?

Not always. Incur and Sustain 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.