I. might ‧ y 1 /ˈmaɪti/ BrE AmE adjective ( comparative mightier , superlative mightiest ) literary
very strong and powerful, or very big and impressive:
the mighty Mississippi river
a mighty army
⇨ high and mighty at ↑ high 1 (26)
II. mighty 2 BrE AmE adverb
American English informal very:
You seem mighty sure of your facts.
They got out of there mighty fast, I can tell you.