Answer: getsit

AnswerCrossword Clue
GETSIT

Says "aha!"

GETSIT

Understands the problem

GETSIT

Understands

GETSIT
Laughs at a joke
GETSIT
Understands the matter
GETSITDigs
GETSITUnderstands the issue
GETSITSees the light
GETSITUnderstands: Colloq.
GETSITIs in on the joke
GETSITCatches on
GETSITSmells the coffee
GETSITJust plain understands