Penny's face maybe when old boy introduces poetry (7)
I believe the answer is:
obverse
'penny's face maybe' is the definition.
I can't tell whether this definition defines the answer.
'old boy introduces poetry' is the wordplay.
'old boy' becomes 'ob'.
'introduces' says to put letters next to each other.
'poetry' becomes 'verse' ('verse' can be a synonym of 'poetry').
'ob'+'verse'='OBVERSE'
'when' acts as a link.
Can you help me to learn more?
(Other definitions for obverse that I've seen before include "Side of coin that shows the principal design" , "Side of a coin with the main design" , "Side of a coin bearing the head" , "Face of a coin" , "Verbose on the opposite side" .)