πρωΐ means “early (in the morning)” (adverb).
“Very πρωΐ, on the first day of the week, they came to the tomb” (Mark 16:2).
Adverb: πρωί (prōi), GK G4745 (S G4404), 12x. Because prōi can designate any time covered in the fourth watch (from 3:00 to 6:00 a.m.), sometimes it refers to very early in the morning, for which we have the phrase “the crack of dawn” (Mk. 13:35; 15:1; 16:2; Jn. 18:28).