Emily Dickinson Lexicon

PLIGHT, v.t. [plite; Sax. plihtan, to pledge, and to expose to danger or rather perhaps to perplexity; Sw. beplichta, to bind; D. pligt, duty, mortgage; G. pflicht, duty, pledge; Dan. pligt, duty, obligation; pligtig, bound, obliged; Sw. plicht. This seems to be the Teutonic form of the Celtic pledge, Fr. pleige, pleiger. L. plico, Gr. πλεκω, It. piegare, Sp. plegar, Fr. plier, Arm. plega, W. plygu, to fold; Sp. pleyto, a covenant or contract; and the G. flechten, to braid, coinciding with the L. flecto, to bend, appears to be of the same family. If the elements are Lg, as I suspect, pledge and plight are formed on the root of lay, Arm. lacqaat. To pledge or plight is to lay down, throw down, set or deposit. Plight may however be more directly from the root of L. ligo, but this is of the same family. See Alloy and Ply.]

1. To pledge; to give as security for the performance of some act; but never applied to property or goods. We say, he plighted his hand, his faith, his vows, his honor, his truth or troth. Pledge is applied to property as well as to word, faith, truth, honor, &c. To plight faith is, as it were, to deposit it in pledge for the performance of an act, on the non-performance of which, the pledge is forfeited.
2. To weave; to braid. – Spenser. Milton. [This is the primary sense of the word, L. plico, but now obsolete.]