capable           adj.  having ability; able; competent
        
        capacity          n.  ability to hold or contain sth
        
        category          n. class or group of things in a complete system of grouping
        
        cease             v.  come or bring (sth) to an end; stop
        
        challenge         n.  ~ (to do sth) invitation or call (to sb) to take part in a game, contest, fight etc to prove who is better, stronger, more able, etc