Use the adverb thus in place of words like therefore or so when you want to sound proper.
Use thus interchangeably with words like consequently, ergo, hence, and just like that. For example, if you want to sound fancy you could say no one showed up for water aerobics, thus the class was cancelled. It had to be thus. Thus is also, rarely, a noun that means a good-smelling gum resin from trees that we don't really use anymore.