المعنى الاصطلاحي :

Performing what is within one's ability of the obligatory and voluntary acts of worship, along with abandoning all prohibitions, which entitles him to be admitted into Paradise and saved from Hell.

الشرح المختصر :

"Kamāl al-imān" (perfection of faith) is to have absolute faith. It is an expression denoting praise and commendation. It means doing what Allah, the Exalted, and His Messenger, may Allah's peace and blessings be upon him, commanded and abandoning what Allah and His Messenger forbade. "Kamāl al-imān" is of two levels: 1. "Wājib" (obligatory), which is attained by fulfilling religious obligations and shunning prohibitions. Lack of such obligatory perfection of faith makes a person's faith deficient in a way that makes him deserving of punishment. However, he is not necessarily described as lacking basic faith and all its parts and branches. Rather, he is described as a disobedient/sinful believer or one who is pious by virtue of his faith and impious by virtue of his sin. Hence, he possesses absolute faith, without which his belonging to Islam is invalid. 2. "Mustahabb (recommended), which is attained by doing what is recommended in excess of performing obligations and by shunning what is disliked in excess of shunning what is prohibited. This is the level of those who are brought near to Allah; those are the beneficent, the foremost, those who hasten to do good deeds from among the prophets and the affirmers of truth.