الاستنشاق والاستنثار
Drawing water into the nostrils and expelling it as a required part of ritual ablution, performed multiple times daily.
إِذَا تَوَضَّأَ أَحَدُكُمْ فَلْيَجْعَلْ فِي أَنْفِهِ مَاءً، ثُمَّ لِيَنْتَثِرْ
“When one of you performs ablution, let him draw water into his nose and then expel it.” (meaning, not a literal translation)
Commentators note the practical hygiene value of regularly clearing the nasal passage, a practice modern otolaryngology recognizes in saline nasal irrigation.