expression, godan verb (-su)
to snap angrily; to lash out in anger
Rare expression meaning to suddenly burst out in anger, often with sharp words. The phrase is somewhat dated and not commonly used in modern conversation.
彼は突然けんつくを食わして、部屋を出て行った。
He suddenly snapped in anger and left the room.
Common kana-mixed spelling; 食わす is the standard kanji for the verb.
Rare kanji spelling using 剣突; the kana form is much more common.
The origin of けんつく is uncertain, but it may be related to 剣突 (sword thrust), suggesting a sharp verbal attack. The phrase is rare and somewhat archaic.