Even number that's odd for the GI (5)
I believe the answer is:
eight
'even number' is the definition.
'eight' can be an answer for 'number' (I've seen this in another clue). I am not certain of the 'even' bit.
'odd for the gi' is the wordplay.
'the gi' can be anagrammed to 'EIGHT'.
Though, I am not sure how this is indicated.
'that's' acts as a link.
Can you help me to learn more?
(Other definitions for eight that I've seen before include "Half a quarter" , "One over this for drunkeness" , "Number that figures in ice-skating?" , "Cardinal number" , "No. of stones in cwt." .)