ک د حk-d-ḥ
(ف) كَدَحَ يَكْدَحُ كَدْحًاkadaḥa yakdaḥu kadḥan: to labour hard, to earn by toil; the original sense is scratching and scraping — as if the labourer wears himself away.
كَادِحkādiḥ (active participle, ism fāʿil): a toiler, one who labours. Twice in the Quran, both in the same verse: ﴿يٰۤأَيُّهَا الْإِنْسَانُ إِنَّكَ كَادِحٌ إِلٰى رَبِّكَ كَدْحًا فَمُلَاقِيْهِ﴾ (Al-Inshiqāq 84:6).