つい

About

つい is an adverb used to indicate that a verb is done unconsciously/unintentionally, or that the speaker "can't help doing X".

つい is often paired with ～てしまう:

E.g. ポテチを見みるとつい買かってしまう。 "If I see chips I can't help but buy them."

つい can also be used temporally, and means "just" as in "just now; just yesterday; etc.".

E.g. ついさっき、怪あやしい人ひとが電車でんしゃに乗のってきた。 "A suspicious person got on the train just now."

Summary

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  つい is an adverb used to indicate that a verb is done unconsciously/unintentionally/that the speaker "can't help doing X"

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  つい can also be used temporally, and means "just" as in "just now; just yesterday; etc."