fom (qetseph (Ho 10:7); aphros (Lu 9:39), aphrizo (Mr 9:18,20), epaphrizo (Jude 1:13)): Qetseph from qatsaph, "to break to pieces," or "to break forth into anger," "to be angry," occurs often in the sense of "wrath" or "anger" (e.g. Nu 1:53; Ps 38:1, etc.), and in this passage has been rendered "twigs" or "chips," "As for Samaria, her king is cut off, as foam (the Revised Version, margin "twigs") upon the water" (Ho 10:7). The other references are from the New Testament. In Jude, evil-doers or false teachers are compared to the "wild waves of the sea, foaming out their own shame." In Mark and Luke the references are to the boy with a dumb spirit who foamed at the mouth.
⇒See the definition of foam in the KJV Dictionary
Alfred Ely Day