I’ll add to the other answers there’s a subtle nuance in paráklētos. A nuance so subtle, you’ll most often see it discussed in explanations of paráklētos, and the evidence for the distinction can be shaky.
Paráklētos follows the pattern of preposition + verbal adjective; it literally means “by-called” (hence, helper or advocate, some you call to be by your side). These kind of compounds are meant to have a distinction of permanence, according to how they are accented. If they are accented on the final syllable (paraklētós, -ḗ, -ón), the state they describe is temporary: it has happened once-off. If they are accented on the antepenult (paráklētos, -on), the state is permanent. So a paraklētós is a guy you can call on at that particular moment, to get you out of a jam. A paráklētos is someone you always call on to get you out of jams, a permanent advocate.
To illustrate with another example I just made up: if you describe someone as perirrapistós, “around-beaten”, you’re saying he’s just been beaten up. If you’re saying someone is perirrápistos, you’re saying they’re constantly being beaten up, that they look all beaten up, maybe that they’re a permanent victim.