Delinquent pair at first illegally entering school (7)
I believe the answer is:
culprit
'delinquent' is the definition.
(thesaurus)
'pair at first illegally entering school' is the wordplay.
'pair' becomes 'pr' (abbreviation).
'at first' indicates taking the first letters.
'entering' indicates putting letters inside.
'school' becomes 'cult' (I can't justify this - if you can you should give a lot more credence to this answer).
The first letter of 'illegally' is 'i'.
'pr'+'i'='pri'
'pri' put within 'cult' is 'CULPRIT'.
Can you help me to learn more?
(Other definitions for culprit that I've seen before include "Perpetrator of a wrongdoing" , "one awaiting trial" , "baddie" , "Offender or guilty party" , "One perpetrating crime" .)