Trancher du grand seigneur = To try and play the lord.
Trancher dans le vif = (lit.) To cut to the quick; (fig.) To set to work in earnest.
Travers
Il a l’esprit de travers = He has an awkward temper; He does not see things as they are; He is cross-grained.
Il me regarda de travers = He looked black (askance) at me.
Il prend tout de travers = He takes everything amiss.
Tréfonds
J’en sais le fonds et le tréfonds = I know the ins and outs of it, the long and the short of it.
[Also: Je connais les tenants et aboutissants de l’affaire.]
Tremper