Punish (8)
'punish' is the definition.
(disciplining is a kind of punishing)
This is all the clue.
(Other definitions for discipline that I've seen before include "Field" , "Branch of knowledge; punish" , "Punishment" , "Training designed to engender self-control" , "Correction" .)
'punish' is the definition.
(I know that punish can be written as penalise)
This is the entire clue.
(Other definitions for penalise that I've seen before include "Disadvantage unfairly" , "See plain (anag.)" , "Perhaps, fine" , "Inflict punishment on" .)
'punish' is the definition.
(thesaurus)
This is the entire clue.
(Another definition for deal with that I've seen is " tackle".)