Abandoned, a.
1. Forsaken, deserted. "Your abandoned streams." Thomson.
2. Self-abandoned, or given up to vice; extremely wicked, or sinning without restraint; irreclaimably wicked ; as, an abandoned villain.
Syn. -- Profligate; dissolute; corrupt; vicious; depraved; reprobate; wicked; unprincipled; graceless; vile. -- Abandoned, Profligate, Reprobate. These adjectives agree in expressing the idea of great personal depravity. Profligate has reference to open and shameless immoralities, either in private life or political conduct; as, a profligate court, a profligate ministry. Abandoned is stronger, and has reference to the searing of conscience and hardening of heart produced by a man's giving himself wholly up to iniquity; as, a man of abandoned character. Reprobate describes the condition of one who has become insensible to reproof, and who is morally abandoned and lost beyond hope of recovery. God gave them over to a reprobate mind. Rom. i. 28.
Shades of meaning
Fernald has no entry of its own for abandoned; he lists it under addicted.
Where he writes about it:
A man may be accustomed to labor, attached to his profession, devoted to his religion, given to study or to gluttony (in the bad sense, given over, or given up, is a stronger and more hopeless expression, as is abandoned). — from addicted
Abandoned tells of the acquired viciousness of one who has given himself up to wickedness. — from addicted