frequent (adj.)
mid-15c., "ample, profuse," from Middle French frequent, or directly from Latin frequentem (nominative frequens) "crowded, repeated," of uncertain origin. Meaning "common, usual" is from 1530s; that of "happening at short intervals, often recurring" is from c.1600.
frequent (v.)
late 15c., from Middle French frequenter, from Latin frequentare "visit regularly," from frequentem (see frequent (adj.)). Related: Frequented; frequenting.