Praying in nothing but a waistcoat
Question
May one pray wearing only a sleeveless waistcoat, when the part [of the body] from the place where the trousers are tied up to the navel — which must be covered — is left exposed?
Answer
Even when the part of the body whose covering is fard remains covered, praying in clothing in which a person could not go to a respectable gathering is makruh; all the more so when even the obligatory (fard) covering of the ‘awra is not fulfilled — in that state the prayer will not be valid at all.
Source: Fatawa Mahmudiyya
Preview. The full text opens with JavaScript enabled.