English Reference

Phrasal verb

build up

Irregular verb

Forms

Infinitive

build up

Past

built up

Past participle

built up

Definition

phrasal verb. To increase or develop something gradually over time. You use this when you want to make something stronger, bigger, or better.

phrasal verb. To increase, strengthen, or develop something by gradual increments. The verb functions transitively when an agent creates the increase and intransitively when a substance or force accumulates.

Examples

“You need to build up your confidence for the job interview.”

“The athlete spent months in the gym to build up her muscle mass before the Olympic trials.”

“The company aims to build up its cash reserves to ensure long-term stability during the upcoming economic downturn.”

Examples

simple

“You need to build up your confidence for the job interview.”

contextual

“The athlete spent months in the gym to build up her muscle mass before the Olympic trials.”

complex

“The company aims to build up its cash reserves to ensure long-term stability during the upcoming economic downturn.”

Usage

Often used with abstract nouns like 'confidence', 'strength', or 'pressure'.

Teaching tip

Contrast with 'increase' (more formal) and 'accumulate' (often used for negative things like debt or dirt).

Pitfall

The traffic is building itself up.

The traffic is building up.

When describing accumulation like traffic or pressure, the verb is intransitive and does not take a reflexive pronoun.

Phrasal verb

Particles

up

Separability

optional

Pattern

build + (object) + up

Synonyms

increasestrengthendevelopaccumulate

Antonyms

weakendecreasediminish

Word family

VERB

NOUN

PHRASAL VERB

build up(B1)

Grammar

Phrasal verbs (introduction)

This entry

Exam level
CambridgeCambridgeCambridge English QualificationsThe exam suite from Cambridge University Press & Assessment, from A1 Movers up to C2 Proficiency. The benchmark names double as CEFR labels.B1 PreliminaryIELTSIELTSInternational English Language Testing SystemThe 0–9 band test co-owned by the British Council, IDP, and Cambridge. Used for university entry, work, and migration.4.0–5.0TOEFL iBTTOEFL iBTTest of English as a Foreign Language, Internet-Based TestETS's academic English test, the standard route for US university admissions. Scored 0–120, with a 1–6 scale since 2026.1–6 scale: 3.0–3.544–71TOEICTOEICTest of English for International CommunicationETS's workplace English test, big in Japan and Korea. Listening & Reading scores 10–990 and tops out at C1.550–784
Frequency
Very common
Level
B1 · Intermediate
Updated

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