not easy; requiring great physical or mental effort to accomplish or comprehend or endure; "a difficult task"; "nesting places on the cliffs are difficult of access"; "difficult times"; "a difficult child"; "found himself in a difficult situation"; "why is it so hard for you to keep a secret?"
requiring much effort and trouble; "the mountain climb was long, steep, and difficult"
muscular and heavily built; "a beefy wrestler"; "had a tall burly frame"; "clothing sizes for husky boys"; "a strapping boy of eighteen"; "`buirdly' is a Scottish term"
not easily borne; wearing; "the burdensome task of preparing the income tax return"; "my duties weren't onerous; I only had to greet the guests"; "a taxing schedule"
mutability in life or nature (especially successive alternation from one condition to another)
a variation in circumstances or fortune at different times in your life or in the development of something; "the project was subject to the usual vicissitudes of exploratory research"
difficult to penetrate; incomprehensible to one of ordinary understanding or knowledge; "the professor's lectures were so abstruse that students tended to avoid them"; "a deep metaphysical theory"; "some recondite problem in historiography"