It's never a good move to make your boss feel dumb.
Also, some people with low self-esteem try to sound smart by using fancy words. It's often easy to notice.
There are exceptions, where some people (e.g. Russel Brand, Stephen Fry) use lots of obscure words to great effect.
@Cleisthenes @jcbrand doesn't even need to be your boss, know your audience and if you can say it simply intelligent people will respect that also
@jcbrand @Cleisthenes one of the downsides of this is in maths/physics textbooks - it can be difficult to find sources that explain the rules that aren't being stated, and once you get these rules you join the club of people who can't be bothered with rereading the rules you take for granted
@jcbrand @Cleisthenes that being said, when something restates the essentials simply and efficiently it's an absolute joy, even if you know them
these books are few and far between
@Cleisthenes @jcbrand I need to read more Shakespeare
@skells @Cleisthenes
Another thing that happens with people who've studied a long time (too long?) is that they start writing everything in acadamese.
Long-winded sentences filled with unnecessary jargon designed to sound intelligent. The ultimate shame/fear of many academics is to be outed as stupid.
Funnily enough it's a sign of intelligence (and real understanding) to be able to convey a complex topic with simple direct language.