A more serious example is suggested by Mary Anne Warren, in her analysis of a familiar anti-abortion argument:
1) It is wrong to kill innocent human beings
2) Fetuses are innocent human beings
Therefore, it is wrong to kill fetuses.
Warren argues that, in fact, this argument faces its own dilemma: either it is guilty of equivocation - or it is guilty of question-begging.
It is easy enough to argue that "innocent human beings" means two different things in the premises - and thus the argument equivocates. For example:
innocent human being in premise 1 = "conscious of moral choice, but not guilty of committing/choosing an immoral act"
innocent human being in premise 2 = "innocent because the fetus is not capable of moral intentions and choices in the first place"
IF two different senses of "innocent human being" are thus at work in the argument - then the argument equivocates: while we might agree that it is wrong to kill innocent human beings in the first sense - this is not immediately relevant to fetuses as innocent human beings in the second sense, and so the conclusion does not follow.