"rising in waves," 1590s, from Latin surgentem (nominative surgens) "rising," present participle of surgere "to rise" (see surge (n.)). In psychology from 1933.
Entries linking to surgent
surge n.
late 15c., "fountain, stream," of uncertain origin, probably from French sourge-, stem of sourdre "to rise, swell," from Latin surgere "to rise, arise, get up, mount up, ascend; attack," contraction of surrigere, from assimilated form of sub "up from below" (see sub-) + regere "to keep straight, guide" (from PIE root *reg- "move in a straight line," with derivatives meaning "to direct in a straight line," thus "to lead, rule"). Meaning "high, rolling swell of water" is from 1520s; figurative sense of "excited rising up" (as of feelings) is from 1510s.