Rashi on Genesis 25:29/רש"י על בראשית כ״ה:כ״ט

1ויזד means boiling, as the Targum renders it.

2והוא עיף AND HE WAS FAINT through murdering people, just as you mention faintness in connection with murder, (Jeremiah 4:31) ‘‘For my soul fainteth before the murderers” (Genesis Rabbah 63:12).