دءب

دَائِبٌ ذ (TA, and so in a copy of the S,) and ↓ دَئِبٌ (TA, and so in two copies of the S,) Striving, labouring, toiling, or exerting himself, and wearying himself, in his work [&c.: or holding on, or continuing, therein: see the verb]. (S, TA.) ― -b2- [Hence,] لَيْلَةٌ دَائِبَةٌ [ A hard, fatiguing, or continuous, night-journey ]. (M and K in art. مرس.) ― -b3- And الدَّائِبَانِ (tropical:) The night and the day; (S, A, K;) which [are so called because they] hold on their course (يَدْأَبَانِ) in their alternating. (TA.)