Look for small tin (4)
I believe the answer is:
scan
'look' is the definition.
(I've seen this before)
'small tin' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'tin' becomes 'can' (synonyms).
's'+'can'='SCAN'
'for' is the link.
(Other definitions for scan that I've seen before include "Analyse a piece of verse for metre" , "Conform to a metrical pattern" , "View quickly" , "Examine quickly" , "Survey - fit in metrically" .)