Noun. From Hebrew.
“A woman whose husband has disappeared or fled, and who cannot remarry until she proves that she is divorced or that her husband is dead”
Agunah, and its plural agunot literally means ‘anchored’ or ‘chained.’ In Jewish marriage, in the case of the man being alive and well (and not missing), he has the choice of offering a get (a notice of divorce) but has no obligation to do so, hence the agunah is anchored to her marriage and her husband.
In fact, those who refer to themselves or are legal viewed as agunot are very active the world over. There are many websites campaigning against these situations where a woman is bolted-down to a certain way of life, and the man effectively has the power to control many aspects of the womans’ life. Such a site for the UK can be found here.