Use pungent to describe a taste or smell that gives a sharp sensation. "What is that pungent odor?" is a polite way of suggesting that someone in the room has BO.
The ultimate source of the word pungent is Latin pungere "to prick, sting." Ginger and mustard seed are examples of pungent spices. Limburger cheese has the distinction of being the most pungent of all cheeses. And if your pet has an accident in the house, there may be a pungent odor. And pungent can be used in a figurative sense: pungent language is stimulating and expressive.