What does 'build up' mean?

Main meanings:

1. Increase or accumulate gradually:
"Traffic is building up on the motorway."
"The tension built up over months."
"Savings build up over time."

2. Strengthen or develop:
"She's building up her client base."
"He built up his confidence slowly."
"Build up your fitness gradually."

3. Praise or promote (often excessive):
"The film was built up as the best of the year." (hyped)
"Don't build it up too much — it might disappoint."

As a noun — "a build-up":
"There was a build-up of traffic." / "The build-up to the event was exciting."

What it implies: Gradual process, not sudden change. Build-up takes time, which is why the image works — things accumulate layer by layer.

Register: Casual to professional. All meanings are common.

Tags: phrasal verbs, gradual change, accumulation, everyday English