Source : Webster's Revised Unabridged Dictionary (1913)

Plangent \Plan"gent\, a. [L. plangens, -entis, fr. plangere to
   beat. See {Plaint}.]
   Beating; dashing, as a wave. [R.] ``The plangent wave.'' --H.
   Taylor.

Source : WordNet®

plangent
     adj : loud and resounding; "plangent bells"; "the plangent
           minority"