The unemployment which occurs in a particular season :like farmers  get job in harvesting season but are unemployed for rest of the seasonal unemployment.
disguised employment occurs when people are working but is not affecting the production ; for ex- if in a field 5 men are needed for production but 8 men are working, if we will remove 3 men it will not affect the production so 3 men are disguised unemployed.
Seasonal employment means a person is not getting work or unemployed during 2 or 3 months.....
disguised employment is when person appears as employed but actually he is not