Answered by Shaykh Faraz Rabbani
Question: Is it preferred for men to wear loose slacks, or to cover using a longer shirt outside of prayer? What about tight jeans?
Answer: In the name of Allah, Most Merciful.
Walaikum assalam wa rahmatullahi wa barakatuh,
It is better to have loose slacks and something (whether a longer shirt, a coat or a jacket) that covers his rear.
Somewhat tight jeans would be at least somewhat disliked and blameworthy. Form-fitting jeans that fully define the shape and form of a part of the body that must be covered with clothing (awra) during normal wear would be sinful to wear and prohibitively disliked.
Men have to obey Allah about dress just like women do.