“Like all the Islamic virtues, zuhd is a golden mean between two extremes; in this case the extremes of worldliness and of monkery."
Imam Ahmad ibn Hanbal defined zuhd as not being pleased when given the things of this world, and not being sorry when they are taken away.
He, RahimahuAllah, also taught that there are three degrees of zuhd:
that of the common people, which involves avoiding what is forbidden (haram),
that of the elite, which is to avoid what is permissible (halal) but unnecessary,
and that of the highest elite, which is to avoid everything which distracts one from God.”
[Abdal-Hakim Murad, translator, The Seventy-Seven Branches of Faith p.56]