Stunt - Russian fighter set up with The Irishman (7)
I believe the answer is:
gimmick
'stunt' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'russian fighter set up with the irishman' is the wordplay.
'russian fighter' becomes 'MiG' (Russian fighter plane manufacturer).
'set up' shows that the letters should be reversed in order (in a down clue, letters go up).
'with' says to put letters next to each other.
'the irishman' becomes 'Mick' (Mick is an example).
'mig' back-to-front is 'gim'.
'gim'+'mick'='GIMMICK'
Can you help me to learn more?
(Other definitions for gimmick that I've seen before include "Trick or device to attract publicity" , "Novelty" , "designed to attract attention" , "PR stunt?" , "Ingenious device to attract attention" .)