impinge comes from Latin impingere ('to strike against, drive into'), from in- ('into') + pangere ('to fix, fasten, drive in'). Morphologically, the prefixed shape matters: the initial element belongs to the recorded formation and helps explain the modern form's surface analysis. In present English, the verb sense is "to encroach upon or have an effect on something", so the historical development ends in a clearly identifiable modern dictionary use. The same base also appears in related forms such as impact, pungent, and poignant, and in derivatives such as impingement, impinger, and impinging. Its semantic neighborhood includes encroach, infringe, intrude, and trespass, which helps locate the modern sense without adding a separate etymological claim. The named historical forms include Latin impingere, Latin pangere, and Proto-Indo-European *pag-.