Equivocal means uncertain or ambiguous. If you ask your teacher what's on an upcoming test and she gives you an equivocal answer, you won't be able to narrow down your studying.
Equivocal is from the Latin aequus "equal, the same" + vocare "to call, to speak" and describes when something is too close to call. An editorial in your local newspaper might make a strong case for new taxes on soda, while another editorial is more equivocal. The fact that equivocal means "uncertain" and unequivocal means "certain" is tricky, and a lot of people get stumped.