the GNU version of the Collaborative International Dictionary of English
adj. characterized by toilsome effort; requiring extreme physical or mental effort.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. characterized by effort to the point of exhaustion; especially physical effort
Word Usage
"Men's tennis players, frustrated by what they describe as a grueling playing calendar and unfairness in the distribution of prize money, are rallying against the sport's governing bodies."