underplay

Short definition from Wiktionary

Noun

1. 1
   The act of underplaying.

Verb

1. 1
   To play in a subordinate, or in an inferior manner; to underact a part.
2. 2
   To make something seem less important than it really is.
3. 3
   To play a low card when holding a high one, in the hope of a future advantage.