Tool drudge noticed
I believe the answer is:
hacksaw
'tool' is the definition.
(hacksaw is a kind of tool)
'drudge noticed' is the wordplay.
'drudge' becomes 'hack' ('hack' can be a synonym of 'drudge').
'noticed' becomes 'saw'.
'hack'+'saw'='HACKSAW'
(Other definitions for hacksaw that I've seen before include "7 for metal" , "One cuts" , "means of cutting lead article?" , "something cutting" , "Metal cutter" .)