A situation, person, group, etc. which is difficult to overcome or deal with.
A problem that is challenging to solve.
Used other than figuratively or idiomatically: see hard, nut, crack.
A place, opportunity, etc. to which it is difficult to gain entry.
An amount that is difficult to finance.
Something that is tough, or difficult.
Someone or something that is strong and resilient.
A tough; Someone or something that acts as a thug or bully.