Meaning of “strictly” - Learner’s Dictionary

strictly

adverb uk us /ˈstrɪktli/
EXACTLY

B2 exactly or correctly:

That's not strictly true.
Strictly speaking (= The rules say), we're not allowed to give you any advice.
ONLY

done or existing for a particular person or purpose:

Her visit is strictly business.
strictly forbidden/prohibited

B2 used to emphasize that something is not allowed

(Definition of “strictly” from the Cambridge Learner’s Dictionary © Cambridge University Press)