These words refer to efforts not easily made or to problems not easily solved. Hard is the most general and informal of these, with a wide range of possible use: hard labour; a hard assignment; a hard struggle. As with the rest of these words, hard does not suggest impossibility of success so much as the extremes of effort that will be required to attain it. Difficult is slightly more formal and somewhat more restricted in range as compared to hard . Where hard might suggest that a burdensome exertion alone is required, difficult frequently stresses a more complex task that may demand control or skill: the hard work of unloading the boxes and the difficult job of weighing and inspecting them. Hard , furthermore, might suggest a firm or unmerciful stand, whereas difficult again stresses complexity, often of a puzzling kind: a hard master; a difficult employer; taking a hard line on these difficult problems.

Laborious and arduous are both more formal than the preceding pair, but are otherwise more closely related to hard than to difficult . Laborious is more restricted than hard in applying almost exclusively to the use of sheer effort or exertion in accomplishing a task, with few suggestions of the skill that might be required and no reference to the complexity of a problem: the laborious job of cleaning up after the flood. Arduous is even more formal than laborious and less restricted in suggesting burdensome effort or almost unmerciful firmness of stand: our arduous struggle to lay the carpet before the guests arrived; unnecessarily arduous regulations.

Perplexing relates closely to difficult , but is more exclusively restricted to describing a task or requirement that is difficult to understand. Thus, while laborious stresses effort, often of a physical kind, perplexing most often suggests the intellectual demands made by a task; it would not be appropriate, one the other hand, to describe effort of any sort: the perplexing job of finding the ten-cent discrepancy in the day’s accounts.

Troublesome and trying also pertain mostly to difficult tasks rather than to the effort required to solve them. Troublesome suggests confusion or disorder or even unpleasant resistance; this contrasts with the intellectual demands made by a perplexing task: the troublesome job of interviewing every one of the suspicious neighbours. Trying , by contrast, is much less specific concerning the kind of resistance it points to; it may suggest any kind of obstacle that taxes the worker’s patience, skill or mental equanimity: too trying to be a baby-sitter for such a spoilt child. The word does beyond perplexing and troublesome in being applicable to effort as well, in which case it suggests the sapping of energy or will: finding the struggle to sit up too trying in her weakened condition.