Is prayer permissible by Tayammum for someone whose fear of obtaining water is mere cowardice without actual cause?
Chapter on Tayammum
Al-Mughni
Book of Purification
Primary text
If a person's fear is due to cowardice and not a cause that would typically warrant such fear, the prayer performed by Tayammum is not valid for him. Imam Ahmad explicitly stated this concerning a man who feared at night when there was nothing to fear; he ruled that he must perform Wudu (ablution).
Supporting text
It is plausible that Tayammum is permissible for him if his fear is intense, as he is then in the position of one fearing a valid cause, and he would make up the prayer later.