Dumb -- like a forgetful politician? (10)
I believe the answer is:
speechless
'dumb' is the definition.
(I know that dumb can be written as speechless)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for speechless that I've seen before include "Struck dumb" , "In shock" , "being forced to improvise?" , "Lost for words" , "Unable to say anything" .)