Man introduced by retiring police officer displaying unique turn of phrase (5)
I believe the answer is:
idiom
'turn of phrase' is the definition.
(I've seen this before)
'man introduced by retiring police officer' is the wordplay.
'man' becomes 'iom' (abbreviation for Isle of Man).
'introduced by' says to put letters next to each other.
'retiring' says the letters should be written in reverse.
'police officer' becomes 'DI' (detective inspector).
'di' backwards is 'id'.
'iom' after 'id' is 'IDIOM'.
'displaying unique' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for idiom that I've seen before include "Phrase such as over the moon" , "Style of speaking characteristic of a specific group" , "Colloquialism" , "Peculiarity of phrase in a language" , "Characteristic style of a period" .)