Stupid, like number tackling current (7)
I believe the answer is:
asinine
'stupid' is the definition.
(I've seen this before)
'like number tackling current' is the wordplay.
'like' becomes 'as'.
'number' becomes 'nine' (nine is a kind of number).
'tackling' is an insertion indicator (I've seen this in other clues).
'current' becomes 'i' (symbol for electric current).
'as'+'nine'='asnine'
'asnine' going around 'i' is 'ASININE'.
(Other definitions for asinine that I've seen before include "Silly like a donkey" , "Absurd" , "Is inane to be foolish" , "Stupid (as a donkey?)" , "Is Annie? (Anag)" .)