What is the difference between a disobedient person (ʿāṣī), a wicked person (fāsiq), and an infidel (kāfir)?

Scholars have agreed that a disobedient person (al-Asi) is one who commits a sin without openly proclaiming it and without persisting in it. A wicked person (al-Fasiq) is one who deviates from obedience and persists in sins. Wickedness (fisq) can even reach the level of disbelief (kufr) if one rejects the commands of Allah the Almighty, as happened with Iblis. As for a disbeliever (al-Kafir), he is one who denies, who does not believe in Allah or His Messenger. The term 'disbelief' (kufr) may sometimes be used to mean wickedness (fisq) or minor disbelief (kufr asghar), as in the Prophet's (peace be upon him) saying: "Insulting a Muslim is wickedness (fusuq), and fighting him is disbelief (kufr)." This is disbelief short of major disbelief (kufr duna kufr). These terms vary in severity: the most severe is disbelief (kufr), then wickedness (fisq), then disobedience (isyan), and each of these has degrees.