… ‘ugly’. If the student wrote that in a test, I would have to mark it wrong and keep going, rather puzzled. Fortunately for me and the student, it was in a revision exercise, so I was was able to find out the reason for the answer. I said ‘What is that word?’. The student replied ‘Handsome’. (Aha!) I said, ‘Read it again, very carefully’. The student replied ‘Hus – band … oh … wife’. So the problem was not not knowing the answer, it was mis-reading the prompt.
But, arguably, the opposite of ‘husband’ is ‘bachelor’, or ‘divorcee’, or ‘widower’ (admittedly less common words, but hardly ‘wrong’). And what does ‘opposite’ mean, anyway? We can say ‘He is my husband; I am his wife’, but we can’t say ‘She is my mother, I am her father’ – we have to say ‘She is my mother, I am her son/daughter’.