intransitive verb
1.
a. : to make acknowledgment : admit
knew what the matter was but never let on
b. : to reveal one's presence
the others were up in the tree house all the time and didn't let on — Agnes N. Keith
2. : to repeat confidential information : tattle
the jealous woman has let on to an old bum — Charlotte Armstrong
3. : pretend
ain't half as sick as she lets on — Edna Ferber