Disguised Unemployment is a situation where more workers are employed in a job than actually required, i.e., their marginal productivity is zero. Removing some workers would not affect total output.
Example: If 5 members of a farm family are working on land that actually requires only 3 workers, the remaining 2 are disguisedly unemployed. They appear employed but contribute nothing extra to production.
Examiners look for two things: a clear definition (surplus workers, zero marginal productivity) and a relevant example. The rural/agricultural example is the most standard one from the textbook. You may also cite an urban example (e.g., extra helpers in a small shop) for variety, but one example is sufficient for 2 marks.