Strange old large cup (3)
I believe the answer is:
odd
'strange' is the definition.
(I know that strange can be written as odd)
'old large cup' is the wordplay.
'old' becomes 'o' (abbreviation).
'large cup' becomes 'DD' (DD is a bra cup size).
'o'+'dd'='ODD'
(Other definitions for odd that I've seen before include "Rum" , "Number not divisible by two" , "Queer" , "Peculiar in uneven way" , "Unmatched" .)