Joe and Leslie, nominally (5)
I believe the answer is:
giles
'joe and leslie nominally' is the definition.
I can't tell whether this definition defines the answer.
'joe and leslie' is the wordplay.
'joe' becomes 'GI' (GI Joe).
'and' means one lot of letters go next to another.
'leslie' becomes 'les'.
'gi'+'les'='GILES'
Can you help me to learn more?
(Other definitions for giles that I've seen before include "Carl _____, newspaper cartoonist" , "Sir - Gilbert Scott, English architect" , "Boy's name" , "Farmer --- of Ham (Tolkien)" , "-- Coren; -- Brandreth" .)