Entries linking to pantsuit
"trousers, drawers," 1840, see pantaloons. The word was limited to vulgar and commercial use at first.
I leave the broadcloth,—coats and all the rest,—
The dangerous waistcoat, called by cockneys "vest,"
The things named "pants" in certain documents,
A word not made for gentlemen, but "gents";
[Oliver Wendell Holmes, "Urania: A Rhymed Lesson," 1846]
Colloquial singular pant is attested from 1893. To wear the pants "be the dominant member of a household" is by 1931. To do something by the seat of (one's) pants "by human instinct" is from 1942, originally of pilots, perhaps with some notion of being able to sense the condition and situation of the plane by engine vibrations, etc. To be caught with (one's) pants down "discovered in an embarrassing condition" is from 1932.
c. 1300, sute, also suete, suite, seute, "a band of followers; a retinue, company;" also "set of matching garments" worn by such persons, "matching livery or uniform;" hence " kind, sort; the same kind, a match;" also "pursuit, chase," and in law, "obligation (of a tenant) to attend court; attendance at court," from Anglo-French suit, siwete, from Old French suite, sieute "pursuit, act of following, hunt; retinue; assembly" (12c., Modern French suite), from Vulgar Latin *sequita, fem. of *sequitus, from Latin secutus, past participle of sequi "to attend, follow" (from PIE root *sekw- (1) "to follow").
Legal sense of "lawsuit; legal action" is from mid-14c. Meaning "the wooing of a woman" is from late 15c. Meaning "set of clothes to be worn together" is attested from late 14c., also "matching material or fabric," from notion of the livery or uniform of court attendants. As a derisive term for "businessman," it dates from 1979. Meaning "matched set of objects, number of objects of the same kind or pattern used together" is from late 14c., as is that of "row, series, sequence." Meaning "set of playing cards bearing the same symbol" is attested from 1520s, also ultimately from the notion of livery. To follow suit (1670s) is from card-playing: "play a card of the same suit first played," hence, figuratively, "continue the conduct of a predecessor."