problem
     n 1: a state of difficulty that needs to be resolved; "she and
          her husband are having problems"; "it is always a job to
          contact him"; "urban problems such as traffic congestion
          and smog" [syn: {job}]
     2: a source of difficulty; "one trouble after another delayed
        the job"; "what's the problem?" [syn: {trouble}]
     3: a question raised for consideration or solution; "our
        homework consisted of ten problems to solve"
Source: WordNet® 2.0