Meaning of “hard line” - Learner’s Dictionary

hard line

noun [ no plural ] us uk

a very strict and severe way of dealing with someone or something:

Judge Tucker has a reputation for taking a hard line on criminals.
hardline adjective us uk /ˌhɑːdˈlaɪn/

a hardline policy on illegal immigrants

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