וַיַּקְרֵב֙ אֶת־הַמִּנְחָ֔ה לְעֶגְל֖וֹן מֶ֣לֶךְ מוֹאָ֑ב וְעֶגְל֕וֹן אִ֥ישׁ בָּרִ֖יא מְאֹֽד׃
Metzudat David on Judges
A stout man: this was also the reason for his death. Because he was fat and a big guy, it was hard for him to stand up and while he was busy with standing up, he was not able to guard himself from Ehud
Metzudat Zion on Judges
STOUT: a big fat guy, as in Kings 1:5:3 "Ten stout cows."