1) disguised unemployment - when more ppl. are engaged in an activity, than the no. of ppl. required for that. for eg. an agricultural field requires 4 laborers but ppl. engaged in the work are 6, then the unemployment for 2 laborers is called disguised unemployment.
2) seasonal unemployment- it refers to an unemployment where a no. of persons r not able to find jobs during some months of the yr!
3) under employment - it refers to an employment situation that is insufficient in some important way for the worker, relative to a standard.