I find I do very badly at word based odd-one-out-type puzzles. It generally seems to be the case (at least, in my experience) that almost any of the items can be chosen as the odd one out, and this choice justified in some way.
A word could be the odd one out because of its structure (number of syllables, where the emphasis falls, etc.), the type of word (adjective, verb, etc.), the relationship of the word to humans (what kind of thing it refers to), the relationship of the word to the world in general (what aspect of the world, field of science, etc. it refers to), how the word is spelt or pronounced (rhymes, starting letters, syllables in common, etc.), and various other things.
There seem to be so many different aspects of a given word that in a given list of four or five things (which is what these puzzles - or at least, the ones that I've encountered - usually offer) there are likely to be multiple candidates for odd-one-out.
Often, when I see the answer to one of these puzzles, it's either something I considered, but discarded in favour of something else, or something I never considered because I was busy trying to find which of the possibilities I'd already thought of it was. It's almost never something which is (to me) more obviously fitting than the possibilities I'd considered.
Now, if everybody else had the same experience, I'd be inclined to assume these questions are just a bit imprecise by nature. Evidently, though, since some people are very good at them, there must be a way to determine which answer is the intended one, and this is very likely to be a transferable skill (in the sense that it can be transferred to new puzzles).
Even if it isn't a learnable skill, I'd still be interested to know what it is. The answer may be that I'm just naturally not good at this sort of puzzle. That's fine. But why? What prior knowledge or mental skill is required to determine which of the possible answers is the one the asker wants?