Laisser voir le bout de l’oreille = To show one’s ignorance (or, true character); To show what one is driving at; To show the cloven hoof.
[A reference to the fable of the ass in the lion’s skin.]
Tenir le haut bout = To have the whip hand.
Boute-en-train
C’est un vrai boute-en-train = He is the very life and soul of the party.
Bouteille
Il n’a rien vu que par le trou d’une bouteille = He has seen nothing of the world.
C’est la bouteille à l’encre que cette affaire = This is a very obscure matter; That affair is as clear as mud.
Boutique
Toute la boutique (pop.) = The whole show (i.e. a thing and everything connected with it); The whole boiling; The whole bag of tricks.