About to kiss a fellow (3)
I believe the answer is:
'a fellow' is the definition.
Both the definition and answer are singular nouns.
Maybe they are linked in a way I don't understand?
'about to kiss' is the wordplay.
'about' becomes 're' ('re' means regarding or about).
'to kiss' becomes 'x' (X can represent a kiss).
Can you help me to learn more?
(Other definitions for rex that I've seen before include "Oedipus - -" , "King (Latin); cat breed" , "King's title" , "See 6" , "King (L.)" .)