Word to refer to someone who takes an oath

I need to find the word for someone who swears an oath in writing a description of a ceremony. E.g.,'At this point in the ceremony, the [insert-word-for-oathtaker] raises her right hand.'

Etymologically, the word that seems most correct is juror, but that seems wrong given how specifically its modern use refers to a member of a jury. Is there a word that fits this situation? Jurat and adjuror both seem to have their own specific meanings today which do not mean simply one taking an oath.

One relevant standard legal term is deponent. From Henry Black, A Dictionary of Law (1910):

DEPONENT. In practice. One who deposes (that is, testifies or makes oath in writing) to the truth of certain facts ; one who gives under oath testimony which is reduced to writing ; one who makes oath to a written statement. The party making an affidavit is generally so called.

Another legal term very similar in meaning to deponent is affiant, which Black defines as follows:

AFFIANT. The person who makes and subscribes to an affidavit. The word is used, in this sense, interchangeably with "deponent." But the latter term should be reserved as the designation of one who makes a deposition.

Yet another potentially relevant term in Black's dictionary is jurator:

JURATOR. A juror; a compurgator ["One of several neighbors of a person accused of a crime, or charged as a defendant in a civil action, who appeared and swore that they believed him on his oath"].

Note that Black's entry for juror does not limit its meaning to "member of a jury":

JUROR. One member of a jury. Sometimes, one who takes an oath ; as in the term "non-juror," a person who refuses certain oaths.

Of these four terms, jurator is the one least encumbered with other common meanings that refer to specific legal roles, but it is a rather unfamiliar (and certainly rarely used) word.