adverb
Etymology: most (I) + -ly
1.
a. : for the most part
the sky was mostly overcast — Elyne Mitchell
b. : usually , generally
it is then that decay mostly sets in — Punch
2. : most
the person whose society she mostly prized — Jane Austen
3. dialect chiefly Scotland : almost
mostly blinded both his eyes — D.M.Moir