instrumenter, v.n., (jur.) to act; to draw up deeds, indentures, etc.; to serve writs; to compose instrumental music.

instrumentiste, n.m., instrumentalist.

à l’insu, prep., unknown to. À mon —, à votre —; unknown to me, unknown to you; unknowingly, unwittingly, unconsciously. A l’— de son père; unknown to his father.

insubmersible, adj., unsinkable.

insubordination, n.f., insubordination.

insubordonné, -e, adj., insubordinate.

insuccès, n.m., failure, want of success.

insuffisamment, adv., insufficiently.

insuffisance, n.f., insufficiency, incapacity.

insuffisant, -e, adj., insufficient, inadequate.