plight

1350–1400; Middle English plit fold, condition, bad condition < Anglo-French (cognate with Middle French pleit plait) fold, manner of folding, condition; spelling apparently influenced by plight² in obsolete sense “danger”

See predicament.

The noun plight, “a condition or state, especially an unfavorable or unfortunate one,” is an etymological minefield. Middle English spellings, dating from the 13th century, include playd, playt, plyte (there are several others). The Middle English forms come from Anglo-French plit, pleit, pleite, plite (with other variants) “situation, condition, state,” literally, “a fold, wrinkle.” (The Middle English and Anglo-French meanings were originally neutral in tone.) The Anglo-French (and Old French pleit, ploit with the same meanings) derives from Vulgar Latin plictum, a noun use of the past participle, from Latin plicitum “folded,” from plicāre “to fold, flex, bend.”
The modern meaning of plight “unfavorable condition” and its current spelling arose toward the end of the 14th century, and is due to a conflation with the native Old English plyht, pliht “peril, risk, danger, risky promise or engagement,” a noun that is the source of the unrelated word plight meaning “pledge.” And therein lies the plight of words too similarly spelled—always in danger of being confused with each other.

before 1000; (noun) Middle English; Old English pliht danger, risk; cognate with Dutch plicht, German Pflicht duty, obligation; (v.) Middle English plighten, Old English plihtan (derivative of the noun) to endanger, risk, pledge; cognate with Old High German phlichten to engage oneself, Middle Dutch plihten to guarantee

The verb plight “to bind (someone) by a pledge, especially of marriage” comes from Old English plihtan “to endanger, compromise, be in peril of, put under risk of forfeiture, pledge.” The connection between promising to marry someone and being in peril isn’t immediately apparent. When this word first appeared in Old English as plihtan, it was with the sense “to endanger or compromise (life, honor, etc.).” It later came to mean “to put something in danger by risking its forfeiture,” which is where “pledge” comes in. If one makes a pledge, one has the solemn duty to fulfill it, at the risk (or peril) of losing one’s honor. This may be an oath you make to a king, or a vow you make to your betrothed.
Germanic cognates of plight include Old Frisian plichta “to hand over possession of,” Middle Dutch plichten “to pledge, commit,” Dutch verplichten “to oblige,” and German verpflichten “to oblige, pledge.”