Is it permissible to pray in clothes that appear to be covering from a distance, but upon closer inspection reveal small, hard-to-notice holes, such as socks and woollen garments?

The intent behind the presence of small holes in the garment is unclear, as is whether skin color is visible through them or not. The garment that covers the 'awrah (private parts) during prayer must be thick enough so that the color of the skin is not visible through it. A thin garment through which the blackness or whiteness of the skin can be seen is not sufficient. If the garment is thick and the color of the skin is not visible through it except upon close inspection and scrutiny, then the prayer performed with it is valid, though it is disliked, and should be repeated within its prescribed time.