clam up

verb

clammed up; clamming up; clams up

intransitive verb

: to become silent

clammed up and refused to talk

Synonyms of clam up

• hush
• dry up
• quiet (down)
• shut up
• settle (down)

Examples of clam up in a Sentence

the little girl clammed up when the doctor came into the room

Recent Examples on the Web

Anyone asked by local or national media over the past few months if they’d been invited to the nuptials clammed up quickly. — Lisa Gutierrez, Kansas City Star, 2 July 2026

On Israel, a lot of candidates have clammed up. — Naaman Zhou, New Yorker, 22 June 2026

The Arrested Development actor clammed up when Smartless cohost Jason Bateman brought up Arnett's ex-wife and their bathroom habits. — Marina Watts, Entertainment Weekly, 22 June 2026

The atmosphere had changed—security kept an eye out for media to turn away at the entrance, and golfers clammed up when asked what was going on at the club. — Dan Alexander, Forbes.com, 18 May 2026

Word History

First Known Use

1916, in the meaning defined above

Rhymes for clam up

• backup
• blowup
• breakup
• buildup
• checkup
• cleanup
• holdup
• hookup
• lineup
• lockup
• makeup
• markup

Kids Definition

clam up

verb

: to become silent

they clammed up when asked for more information