“hard”

Involving great effort, difficulty, or endurance.

“The arduous climb through the frozen pass left even the veteran soldiers questioning their resolve.”

Best for: Works well in formal writing, adventure narratives, or describing sustained physical or mental effort.

Exhaustingly demanding and severe in its toll on the body or mind.

“The grueling twelve-hour shift at the foundry left his hands blistered and his spirit hollow.”

Best for: Strong and vivid; fits journalism, sports writing, and gritty realistic fiction.

Requiring extraordinary strength or effort, as if worthy of the hero Hercules.

“Restoring the flooded archive was a Herculean task that consumed an entire decade.”

Best for: Best used sparingly for truly monumental challenges; carries classical weight and gravitas.

Involving an oppressive burden of labor, obligation, or difficulty.

“The onerous terms of the contract bound him to work he had long grown to resent.”

Best for: Ideal for legal, professional, or literary contexts emphasizing burden and obligation.

Demanding extreme precision, care, or rigorous effort without tolerance for error.

“She thrived under the exacting standards of the master watchmaker who accepted nothing less than perfection.”

Best for: Great for craft, professional, and intellectual contexts where precision defines the difficulty.

Impenetrably dark or forbidding in difficulty, drawn from the river Styx of the underworld.

“The stygian complexity of the ancient manuscript defeated even the most seasoned cryptographers.”

Best for: Rare and poetic; use when describing difficulty that feels dark, crushing, or mythically overwhelming.