Use drugs to take part in school sport? (4)
I believe the answer is:
dope
'use' is the definition.
(I know that dope is a more specific form of do drugs)
'drugs to take part in school sport?' is the wordplay.
'drugs' becomes 'E' (abbreviation for ecstasy).
'to' means one lot of letters go next to another (I've seen this in other clues).
'take' becomes 'do' (eg taking or doing drugs).
'part in school sport?' becomes 'p' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'do'+'p'='dop'
'e' put after 'dop' is 'DOPE'.
Can you help me to learn more?
(Other definitions for dope that I've seen before include "Dolt -- drug" , "Information; nitwit" , "Idiot; information" , "But does he understand" , "Booby" .)