To promise or bind by a solemn pledge, especially to betroth.
To give or pledge (one's word or oath, for example).
n. A solemn pledge, as of faith.
[Middle English plighten, from Old English plihtan, to endanger, put at risk, from pliht, danger, risk; see dlegh- in Indo-European roots.] plight'er n.
(plīt) 