Bound vs Constrain

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

Bound

Top 2,000 (common) B2 adjective

Constrain

Top 3,000 (common) B1

Most common: Bound

	Bound	Constrain
Pronunciation	🇬🇧 /["/baʊnd/"]/ 🇺🇸 /["/baʊnd/"]/	🇬🇧 //kənˈstreɪn// 🇺🇸 //kənˈstreɪn//
Meaning	To move quickly or jump in a way that shows energy.	To limit or restrict something.
Example	She felt bound by the promises she had made to her friends.	The budget will severely constrain our project options.
Register	Neutral	Neutral
How common	Top 2,000 (common)	Top 3,000 (common)
CEFR level	B2	B1
Part of speech	adjective
Collocations	be, seem, almost, be, feel, become, absolutely, irrevocably, by law, by, be, homeward, outward, for, be, homeward, outward, for	constrain resources, constrain choices, constrain behavior, constrain development, constrain growth
Antonyms	slow, linger, hesitate	liberate, free, allow
Common mistakes	Used incorrectly as a synonym for 'bound' in legal contexts (e.g., confused with 'bound by law')., Confused with 'bounced' in context of movement., Mixing with 'bond,' which refers to a connection or relationship.	Confused with 'restrain' — they have different meanings., Mistakenly use it with non-animate objects., Omitting the object when using 'constrain'.
Usage notes	Used in both physical and metaphorical contexts. Commonly used in literary texts to describe movement. Less appropriate in casual spoken language.	Use 'constrain' in contexts where limitations are imposed intentionally. Avoid in casual or colloquial speech.

See it in real clips

The Lord Of The Rings › The Fellowship Of The Ring

Each race is bound to this fate, this one doom.

A Knight Of The Seven Kingdoms › S1 E1

Bound for the tourney yourself?

Peaky Blinders › S1 E1

All bound for Libya.

The Lord Of The Rings › The Fellowship Of The Ring

Each race is bound to this fate, this one doom.

A Knight Of The Seven Kingdoms › S1 E1

Bound for the tourney yourself?

Bound

Frequently asked questions: Bound vs Constrain

What's the difference between Bound and Constrain?

Bound: To move quickly or jump in a way that shows energy. Constrain: To limit or restrict something.

Which is more common: Bound and Constrain?

Bound is the most common in everyday English.

Which is more advanced: Bound and Constrain?

Bound is the highest level, at B2, on the CEFR scale.

Are Bound and Constrain the same CEFR level?

Bound: B2, Constrain: B1 on the CEFR scale.

Can you show an example of each?

Bound: She felt bound by the promises she had made to her friends. Constrain: The budget will severely constrain our project options.

Can I use Bound and Constrain interchangeably?

Not always. Bound and Constrain 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.