matchmaker(n = noun.person) marriage broker, matcher - someone who arranges (or tries to arrange) marriages for others;
is a kind of go-between, intercessor, intermediary, intermediator, mediator

1.  One who makes matches for burning or kinding. [1913 Webster]

2.  One who tries to bring about marriages. [1913 Webster]

matchmaker, n. a person fond of scheming to bring about marriages.

Derivative:
matchmaking n.

N  marriage, matrimony, wedlock, union, intermarriage, miscegenation, the bonds of marriage, vinculum matrimonii, nuptial tie, married state, coverture, bed, cohabitation, match, betrothment, wedding, nuptials, Hymen, bridal, espousals, spousals, leading to the altar, nuptial benediction, epithalamium, sealing, torch of Hymen, temple of Hymen, hymeneal altar, honeymoon, bridesmaid, bridesman, best man, bride, bridegroom, married man, married woman, married couple, neogamist, Benedict, partner, spouse, mate, yokemate, husband, man, consort, baron, old man, good man, wife of one's bosom, helpmate, rib, better half, gray mare, old woman, old lady, good wife, goodwife, feme, feme coverte, squaw, lady, matron, matronage, matronhood, man and wife, wedded pair, Darby and Joan, spiritual wife, monogamy, bigamy, digamy, deuterogamy, trigamy, polygamy, mormonism, levirate, spiritual wifery, spiritual wifeism, polyandrism, Turk, bluebeard, unlawful marriage, left-handed marriage, morganatic marriage, ill- assorted marriage, mesalliance, mariage de convenance, marriage broker, matrimonial agency, matrimonial agent, matrimonial bureau, matchmaker, schatchen, married, one, one bone and one flesh, marriageable, nubile, engaged, betrothed, affianced, matrimonial, marital, conjugal, connubial, wedded, nuptial, hymeneal, spousal, bridal, the gray mare the better horse, a world-without-end bargain, marriages are made in Heaven, render me worthy of this noble wife, si qua voles apte nubere nube pari.