Cela se mange froid = (lit.) That is eaten cold; (fig.) That is a matter of no importance; That is easily done.
Il n’a pas froid aux yeux = He is a plucky fellow.
Il fait un froid de loup = It is terribly cold.
Front
Vous heurtez de front tous ses préjugés = You run counter to (or, openly attack) all his prejudices.
Il mène plusieurs affaires de front = He carries on several schemes simultaneously; He has many irons in the fire.
Marcher de front = To walk abreast.
Frotter
*Qui s’y frotte s’y pique = Whoever meddles with it, will smart for it.
[Compare the motto of the Order of the Thistle: Nemo me impune lacessit.]