Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.

EXAMPLES FROM THE WEB FOR CLAM UP

A little general chitchat once in a while, then she'd clam up to do a little mental orbit figuring.

WORD ORIGIN

bivalve mollusk, c.1500, in clam-shell, originally Scottish, apparently a particular use from Middle English clam "pincers, vice, clamp" (late 14c.), from Old English clamm "bond, fetter, grip, grasp," from Proto-Germanic *klam- "to press or squeeze together" (cf. Old High German klamma "cramp, fetter, constriction," German Klamm "a constriction"). If this is right then the original reference is to the shell. Clam-chowder attested from 1822. To be happy as a clam is from 1833, but the earliest uses do not elaborate on the notion behind it, unless it be self-containment.

MORE RELATED WORDS FOR CLAM UP

Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.