A noun appearing as G. uimoth “a whale” in the Gnomish Lexicon of the 1910s, literally meaning “sheep of the waves”, a combination of G. uin “†wave” and G. moth “sheep” (GL/74). In the Gnomish Lexicon, the sense “wave” for uin was marked as archaic (†), and it also came to mean “whale” in ordinary speech after the name of the great whale Uin.

Neo-Sindarin: For purposes of Neo-Sindarin, I would update this word to ᴺS. gwimmam “whale”, a combination of gwing “foam” and [ᴺS.] bam “sheep”.