A little problem reported with stove pipe? (8)
I believe the answer is:
somewhat
'a little' is the definition.
(I've seen this before)
'problem reported with stove pipe?' is the wordplay.
'problem' becomes 'sum' (arithmetic problem).
'reported' indicates a 'sounds like' (homophone) clue.
'with' becomes 'w' (abbreviation).
'stove pipe?' becomes 'hat' (stove pipe is a type of hat).
'sum' is a homophone of 'some'.
'some'+'w'+'hat'='SOMEWHAT'
(Other definitions for somewhat that I've seen before include "To an extent, a little" , "Moderately" , "Partially, to a degree" , "Quite" , "To a moderate extent" .)