Root about in the tin for the drawing (7)
I believe the answer is:
cartoon
'the drawing' is the definition.
(I've seen this before)
'root about in the tin' is the wordplay.
'about' indicates anagramming the letters.
'in the' means one lot of letters goes inside another.
'tin' becomes 'can' ('can' can be a synonym of 'tin').
'root' anagrammed gives 'rtoo'.
'rtoo' put within 'can' is 'CARTOON'.
'for' is the link.
(Other definitions for cartoon that I've seen before include "Comical drawing" , "could make one laugh" , "Humorous sketch" , "One may find it funny" , "Animated drawing" .)