From madness, putting out small idiotic remark (7)
I believe the answer is:
inanity
'idiotic remark' is the definition.
(an inane comment)
'from madness putting out small' is the wordplay.
I cannot really see how this works, but
'from' could be 'in' (I've seen this in other clues) and 'in' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
(Other definitions for inanity that I've seen before include "Folly" , "Being silly" , "Puerility" , "Silliness in a tiny way" , "Foolishness" .)