self-deprecating

UK: /ˌsɛlfˈdɛprɪkeɪtɪŋ/ US: (self′dep′ri kā′ting, self′-)

WordReference Random House Unabridged Dictionary of American English © 2026

self-dep•re•cat•ing  (self′dep′ri kā′ting, self′-), adj. 

1. belittling or undervaluing oneself;
   excessively modest.

Also, self-dep•re•ca•to•ry (self′dep′ri•kə•tôr′ē, -tōr′ē, self′-). self′-dep′re•cat′ing•ly, adv. 
self′-dep•re•ca′tion, n. 

Collins Concise English Dictionary © HarperCollins Publishers::

self-deprecating, self-depreciating, self-deprecatory adjective

1. having a tendency to disparage oneself