1. Too simple to bother detailing.
2. Not worth the speaker's time.
3. Complex, but solvable by methods so well known that anyone not utterly cretinous would have thought of them already.
4. Any problem one has already solved (some claim that hackish
trivial usually evaluates to
I've seen it before
). Hackers' notions of triviality may be
quite at variance with those of non-hackers. See
nontrivial,
uninteresting.
The physicist Richard Feynman, who had the hacker nature to an
amazing degree (see his essay Los Alamos From Below
in
Surely You're Joking, Mr. Feynman!), defined
trivial theorem as one that
has already been proved
.