Heavyweight out with some of the boys? (5)
I believe the answer is:
tyson
'of the boys?' is the definition.
The definition suggests a singular noun which matches the answer.
'heavyweight out with some' is the wordplay.
'heavyweight' becomes 'ton' (a ton weighs a lot).
'out' is an insertion indicator.
'with some' becomes 'ys' (I can't justify this - if you can you should give a lot more credence to this answer).
'ton' going around 'ys' is 'TYSON'.
Can you help me to learn more?
(Other definitions for tyson that I've seen before include "Mike ..., former US prizefighter" , "26 4 [RING MASTER]" , "Undisputed world heavyweight champion, 1987" , "Youngest ever undisputed world heavyweight boxing champion, b, 1966" , "American world heavyweight champion, b. 1966" .)