Definition of exactly adverb from the Oxford Advanced Learner's Dictionary

Oxford3000

exactly

adverb
ɪɡˈzæktli
 
; ɪɡˈzæktli
 
 
1 used to emphasize that something is correct in every way or in every detail
Synonym
precisely
I know exactly how she felt.Do exactly as I tell you.It happened almost exactly a year ago.It's exactly nine o'clock.You haven't changed at all—you still look exactly the same.His words had exactly the opposite effect.Your answer is exactly right.It was a warm day, if not exactly hot.
2 (informal) used to ask for more information about somethingWhere exactly did you stay in France? (disapproving) Exactly what are you trying to tell me?3 used as a reply, agreeing with what somebody has just said, or emphasizing that it is correct‘You mean somebody in this room must be the murderer?’ ‘Exactly.’
Idioms

not exactly

(informal)1 used when you are saying the opposite of what you really meanHe wasn't exactly pleased to see us—in fact he refused to open the door.It's not exactly beautiful, is it? (= it's ugly)2 used when you are correcting something that somebody has said‘So he told you you'd got the job?’ ‘Not exactly, but he said they were impressed with me.’