1540s, from French tumultuous (Modern French tumultueux), from Latin tumultuosus "full of bustle or confusion, disorderly, turbulent," from tumultus (see tumult). Related: Tumultuously; tumultuousness.
It forms all or part of: butter; contumely; creosote; intumescence; intumescent; protuberance; protuberant; psychosomatic; somato-; -some (3) "body, the body;" soteriology; Tartuffe; thigh; thimble; thousand; thole (n.); thumb; tumescent; tumid; tumor; truffle; tuber; tuberculosis; tumult; tyrosine.
It is the hypothetical source of/evidence for its existence is provided by: Avestan tuma "fat;" Greek tylos "callus, lump;" Latin tumere "to swell," tumidus "swollen," tumor "a swelling;" Lithuanian tukti "to become fat;" Lithuanian taukas, Old Church Slavonic tuku, Russian tuku "fat of animals;" Old Irish ton "rump."
1520s, "lack of regular arrangement;" 1530s, "tumult, disturbance of the peace;" from disorder (v.). Meaning "an ailment, a disturbance of the body or mind" is by 1704.
"violent muscular spasms, rapidly alternating contraction and relaxation of a muscle," 1817, from Modern Latin, from Greek klonos "turmoil, any violent motion; confusion, tumult, press of battle," a word of uncertain origin. Related: Clonicity.