Such boys still have some schooldays! (3)
I believe the answer is:
old
'such boys still' is the definition.
Both the definition and answer are adjectives. Perhaps they are linked in a way I don't understand?
'some schooldays' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'OLD' can be found hidden inside 'schooldays'.
'have' is the link.
Can you help me to learn more?
(Other definitions for old that I've seen before include "Venerable" , "At an early stage - at a late stage" , "Much-used" , "Long-lived" , "Senescent" .)