Of persons: Devoting earnest attention or pains; paying regard or attention; attentive, heedful, assiduous, intent. Const. to, about, on, upon, or…

Assiduous, diligent, busy.

Of persons: ‘Constant in application, persevering in endeavour, assiduous’, industrious; ‘not idle, not negligent, not lazy’ (Johnson).

Of persons or agents: = assiduous, adj. 1.

Characterized by or showing application, endeavour, or effort; painstaking, zealous, keen; efficient. Chiefly with in (also †after, †of, †to) some…

Of persons or agents: Diligent, active, constant in application to the matter in hand; assiduous, persistent.

Of persons or agents: Constant in application to the business in hand, persevering, sedulous, unwearyingly diligent.

Very diligent.