3 down
An
idiot
picked
up
sponge
(5)
An idiot picked up sponge (5)
hints
0
checks
0
hints
The definition is at the end of the clue.
How the clue works
Look at sponge at the end — that's your definition. An idiot gives you A FOOL, and then picked up is your reversal indicator, flipping A FOOL backwards to give you the answer.