“Verbally there is a very general agreement; for both the general run of men and people of superior refinement say that it is happiness, and identify living well and faring well with being happy; but with regard to what happiness is they differ, and the many do not give the same account as the wise. For the former think it is some plain and obvious thing like pleasure, wealth or honour…”
The original, 1095a:
ὀνόματι μὲν οὖν σχεδὸν ὑπὸ τῶν πλείστων ὁμολογεῖται: τὴν γὰρ εὐδαιμονίαν καὶ οἱ πολλοὶ καὶ οἱ χαρίεντες λέγουσιν, τὸ δ᾽ εὖ ζῆν καὶ τὸ εὖ πράττειν ταὐτὸν ὑπολαμβάνουσι τῷ εὐδαιμονεῖν: περὶ δὲ τῆς εὐδαιμονίας, τί ἐστιν, ἀμφισβητοῦσι καὶ οὐχ ὁμοίως οἱ πολλοὶ τοῖς σοφοῖς ἀποδιδόασιν. οἳ μὲν γὰρ τῶν ἐναργῶν τι καὶ φανερῶν, οἷον ἡδονὴν ἢ πλοῦτον ἢ τιμήν
All three instances of happy in the passage are translated as eudaimonia; the “being happy” word is just the equivalent verb, eudaimonein.
There are a lot of words for happiness, with different etymologies and connotations. The LSJ gloss of eudaimōn (literally, good-daemon) is “blessed with a good genius”. So: your guardian angel is good to you. (The “genius” is the old-fashioned equivalent of the guardian angel.)
Then again, happy in English originally means “lucky” (as in hap-penstance), which is what eutykhēs means. The etymology pushes the word down a certain track; but it it isn’t the full story of what the word means.
To my modern ears, eudaimonia means you’re in a good place, things have worked out well for you. (Etymologically, the daemon has seen to that, though you don’t need a guardian angel to end up in a good place.) And as Aristotle says, that’s not just because you happen to be a stud, loaded, or a celebrity.