Poster impresses one Scottish golf club perhaps (7,4)
I believe the answer is:
playing card
'club perhaps' is the definition.
(club is a kind of playing card)
'poster impresses one scottish golf' is the wordplay.
'poster' becomes 'placard' (synonyms).
'impresses' is an insertion indicator (some letters pressed into others).
'one scottish' becomes 'yin' ('yin' can mean 'one' in Scottish dialect).
'golf' becomes 'g' (phonetic alphabet: alpha, bravo, charlie etc.).
'yin'+'g'='ying'
'placard' enclosing 'ying' is 'PLAYING-CARD'.
(Other definitions for playing card that I've seen before include "heart, say" , "One of the pack" .)