Old dog biting Charlie? Result! (5)
I believe the answer is:
occur
'result' is the definition.
(thesaurus)
'old dog biting charlie?' is the wordplay.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'dog' becomes 'cur' (cur is a kind of dog).
'biting' is an insertion indicator (I've seen this in other clues).
'charlie?' becomes 'c' (phonetic alphabet: alpha, bravo, charlie etc.).
'cur' placed around 'c' is 'ccur'.
'o'+'ccur'='OCCUR'
(Other definitions for occur that I've seen before include "Happen - to come to mind" , "Spring to mind" , "Happen, transpire" , "Turn up" , "exist" .)