In quarrel notice piercing tool (7)
I believe the answer is:
bradawl
'piercing tool' is the definition.
(I've seen this before)
'in quarrel notice' is the wordplay.
'in' means one lot of letters goes inside another.
'quarrel' becomes 'brawl' (brawling is a kind of quarrelling).
'notice' becomes 'ad' (both can mean an advertisement).
'brawl' going around 'ad' is 'BRADAWL'.
(Other definitions for bradawl that I've seen before include "Boring article" , "it has a point" , "Hole-making tool" , "one that bores" , "One may be boring" .)