vain /veɪn 
/ ▸ adjective 1 having or showing an excessively high opinion of one's appearance, abilities, or worth: their flattery made him vain
a vain woman with a streak of snobbery.
2 [attributive] producing no result; useless: a vain attempt to tidy up the room
the vain hope of finding work.
▪ having no likelihood of fulfilment; empty: a vain boast.
– PHRASES in vain /ˌɪn ˈveɪn /
without success or a result: they waited in vain for a response.
take someone's name in vain
use someone's name in a way that shows a lack of respect. – DERIVATIVES vainness /ˈveɪnnəs / noun – ORIGIN Middle English (in the sense ‘devoid of real worth’): via Old French from Latin vanus ‘empty, without substance’.
EnglishOxford Dictionary of English
