What is meant by abandonment (al-hajr), and in what sense is it understood within the context of fatwas stating that a wicked person (fasiq) should not be abandoned except for an overriding benefit, taking into account the multiplicity of types of abandonment?

It is permissible to boycott a transgressor (fasiq) if there is hope that this will lead him to abandon his sin. This boycott is implemented through speech. An example of this is what the Companions did with the three who lagged behind from the battle. It is reported in Sahih Muslim that Abdullah ibn Mughaffal boycotted a relative of his who used to throw pebbles after he had forbidden him, and he said to him: "I will never speak to you." Imam An-Nawawi mentioned that this hadith indicates the permissibility of boycotting people of innovation (bid'ah) and transgression (fusuq).