Search Result for "underact": 
Wordnet 3.0

VERB (1)

1. act (a role) with great restraint;
[syn: underact, underplay]

The Collaborative International Dictionary of English v.0.48:

Underact \Un`der*act"\, v. t. To perform inefficiently, as a play; to act feebly. [1913 Webster]
WordNet (r) 3.0 (2006):

underact v 1: act (a role) with great restraint [syn: underact, underplay] [ant: ham, ham it up, overact, overplay]