Number the GI confused (5)
I believe the answer is:
eight
'number' is the definition.
(eight is a kind of whole number)
'the gi confused' is the wordplay.
'confused' indicates an anagram.
'the'+'gi'='thegi'
'thegi' is an anagram of 'EIGHT'.
(Other definitions for eight that I've seen before include "What's next?" , "Four twos" , "Number; rowing boat" , "Cube of two" , "Chaps having row" .)