Cela est trop fort (or, raide) = That is too bad; That is
beyond a joke.
Cela est par trop fort = That is really too bad.
[This par is derived from the Latin intensive particle per,
as in perhorridus. In French one finds such words as parfaire,
parachever, and in old French this prefix was separable. Thus,
tant il est parsage might be written tant il par est sage. So,
Cela est par trop fort = Cela est trop parfort.]
C’est un esprit fort = He is a freethinker.
Voilà qui est fort = That is rather strong.
Ça, ce n’est pas fort = That is very tame; There is not much in
that.
A plus forte raison = All the more reason; A fortiori.
Il faut que je parle, c’est plus fort que moi = I must speak, I
cannot help it.
Le plus fort est fait = The worst is over; The most difficult
part is done.
Savoir le fort et le faible de l’affaire = To know the ins and
outs of the matter.
Le fort portant le faible = One thing with another; On an
average.
*“La raison du plus fort est toujours la meilleure” = Might is
right; There is no arguing with a large fist.
[La Fontaine, Fables, i. 10, Le loup et l’agneau.]
Fort comme un Turc = As strong as a horse.
“Ou tôt ou tard, ou près ou loin,
Le fort du faible a besoin” =
The lion had need of the mouse.
[Génin, Récréations, ii. 250.]