amol

hefty

large and heavy. eg: He was a tall, hefty man. Her boss gave her a hefty raise. a hefty dose of irony

submerge

to make (someone or something) go under the surface of water or someother liquid: to cover (someone or something) with a liquid. eg: The town was submerged by the flood.

stringent

very strict or severe. eg: principal took stringent action against the students.

contaminate

to make (something) dangerous, dirty, or impure by adding something harmfulor undesirable to it eg: Don't touch the microchip or the oil on your hands will contaminate it. Make sure the white paint is not contaminated by any of the other colors.