Definition of espouser in English:

espouser

noun

See espouse

‘I'm wary of applying amateur psychology to politics but it is surely the case that the espousers of far-fetched conspiracies, convinced that they need to ‘open our eyes’, succeed only in giving us a window on their own insecurities.’
‘Thirty years on, they are two of the most well-known espousers of a Western-style Buddhism.’