Der kleine Mann ist enttäuscht.

actually an interesting word to dissect... Tausch = change / exchange (instead of one thing I have put another)

täuschen = to cheat s.o by telling/giving/showing him a thing for another

ent- has the same effect on a word as a needle on a balloon

The Mann was ge-täusch-t (perfect participle) by some hope, some illusion. Now the balloon has popped. He is disillusioned.

However it translates as: disappointed