There are at least
two usages of "trivial". One is to describe answers, and the other is to describe questions/tasks.
Answers: A trivial answer is
something which is either immediately self-evident or which conveys no information.
Questions/Tasks: A trivial question can perhaps be defined as
something for which either the answer or the method of finding the answer is known by the person asked the question.
Answers: When asked to describe yourself, a nontrivial answer would be, "My name is Joe Schmoe. I'm 5'10" and weigh 170
lbs." A trivial answer would be, "I'm a
human. I know English."
Questions/Tasks: In mathematics, computing the values of integrals is a trivial task, (even though it can be
hard), because the methods for computing integrals are known.