gen. Requiring great effort, arduous, difficult. Chiefly with infinitive. Obsolete.

Characterized by or involving great effort, exertion, pain, or discomfort; laborious, exhausting; arduous, difficult. Cf. travailsome, adj.

= laborious, adj. (in various senses).

Characterized by or involving hard work or exertion; requiring much time or effort; arduous, tiring; painstaking, tiresomely difficult. Also of a…

Characterized by or involving great effort, exertion, pain, or discomfort; laborious, exhausting; arduous, difficult; = travailous, adj.

Requiring, involving, or characterized by hard work or exertion; = laborious, adj. 2.

Demanding great effort or commitment; characterized by or involving stringent or exacting standards; (also, of a religious practice, etc.)…

Of a labour or task: Difficult or hard to accomplish as Hercules' labours were; requiring the strength of a Hercules; excessive, immense.

figurative from 2 3: †‘Imperious’, stern and rough (obsolete); (of soil, etc.) obstinate, refractory, intractable; (of weather, etc.) rough and…

Of a task, undertaking, etc.: requiring so much effort to complete as to seem impossible; very difficult or demanding. Cf. Herculean, adj. 3.

Of a task, work, etc.: taxing, laborious, difficult; spec. requiring close attention; intricate, fine-detailed.