insist (v.) Look up insist at Dictionary.com
1580s, from French insister (14c.) or directly from Latin insistere "take a stand, stand on, stand still; follow, pursue; insist, press vigorously, urge, dwell upon," from in- "upon" (from PIE root *en "in") + sistere "take a stand," from PIE *si-st-, reduplicated form of root *sta- "to stand, make or be firm." Perhaps in some cases a back-formation from insistence. Related: Insisted; insisting.