Psychologically healthy....
Doesn't have to mean having zero issues, but having less of them (running wildly, madly) in their life and most importantly, those issues have less power in their lives.
Doesn't have to mean being untouchable, but being able to not let any problems and matters control their lives, behaviors, attitudes.
Doesn't have to mean being all happy everytime, but having a willingness to feel everything-- yet being free from their control.
Doesn't have to mean having a rose-tinted glasses / perfect outlook on the world and its meaning, but a healthy perspective from which it's possible to build their lives, and psyche, in a good, non-damaging manner.
Doesn't have to mean being extroverted (outgoing, charming, etc) or introverted (calm, rational, relaxed), but being able to express yourself in a manner that is both a) free, and b) doesn't hurt them, or others.
Doesn't have to mean being perfect or successful or flawless, but being able to live well and contribute in society without compromising themselves -and- harming others.
Doesn't have to mean having a perfect wisdom, but having a willingness to experience, to learn, to be wrong.
Now psychology unhealthy people..
Paraphrasing from Anna Karenina; "“All happy families are alike; each unhappy family is unhappy in its own way.”