NOUN - Sway, Wave

eg. The stillness was disturbed by an almost unnoticable, yet measurable undulation of the tide.

ADJECTIVE - attempting to avoid notice or attention, typically because of guilt or a belief that discovery would lead to trouble; secretive

eg. He watched her furtive glances from a distance.

ADJECTIVE - eager or quick to argue or fight; aggressively defiant.

eg. They behaved in the most brutal and truculent manner.

ADJECTIVE - believing the worst of others, especially that all acts are selfish.

eg. I'm quite cynical about whether politicians genuinely do good deeds for others rather than for publicity.

ADJECTIVE - not showing due respect for another person.

eg. Even though Mary needed a new vacuum cleaner, the impudent attitude of the sales clerk made her decide to leave the store.