When I was a child, they would have called someone like that (in the sense of coward) "maricón" or "mariquita", which are offensive words for a gay male. But luckily, this has changed. It is quite unusual know to use those words with that sense. We still use like a lot the word
which is a general, not kind word for a male homosexual too, but two things happened with that word. For one hand, it lose strength, so it has become less harmful and even many gay people use it to refer to themselves. On the other hand, the word has become wider, not only involving gay people know. It has mutated to something like "bastard" but not too strong but rather mildly unless it is said in a very bad tone.