1580-90; < Latininsistere to stand still on, persist in, equivalent to in-in-2 + sistere to stand, make stand, reduplicated derivative from base of stāre to stand
1580s, from Latin insistere "persist, dwell upon, stand upon," from in- "upon" (see in- (2)) + sistere "take a stand" (see assist). Perhaps in some cases a back-formation from insistence. Related: Insisted; insisting.