Q 1: What is
the definition of the Ajnaby or Ajnabiyyah?
Is the uncle's son considered Ajnaby to his female cousin? Is it permissible for them to shake hands?
A:
An Ajnaby man is a man who is not a Mahram (spouse or permanently unmarriageable relative) for a woman. The Mahrams are mentioned in the Ayah (Qur'anic Verse) which begins with:
And tell the believing women to lower their gaze (from looking at forbidden things)
(Surah Al-Nour)
This also applies to women. So, a male cousin is considered Ajnaby to a female cousin and it is unlawful for them to shake hands. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.