introspect (v.)

1680s, "to look into" (transitive), from Latin introspectus, past participle of introspicere "look at, look into; examine, observe attentively," from intro- "inward" (see intro-) + specere "to look at" (from PIE root *spek- "to observe"). Meaning "look within, search one's feelings or thoughts" is from 1875, a back-formation from introspection. Related: Introspected; introspecting.