The Spanish hongo, for “mushroom,” doesn’t sound anything like its English counterpart “mushroom.” But it does come from the Latin fungus from which we get the English synonym for mushroom… fungus.
The relation between hongo and fungus is easy to remember if we remember that, as Latin evolved into Spanish, the initial f- (followed by a vowel) usually transformed into an h-. Thus, the f-n-g for fungus maps exactly to the h-n-g of hongo.