the word 'toilsome' is a compound formed from the noun 'toil' and the adjectival suffix '-some'. 'toil' entered english from the old french 'toillier', which meant to struggle, entangle, or agitate, tracing back to the latin 'tudiculare', meaning to crush or beat, related to 'tudes', a hammer. the suffix '-some' is a native english element from old english '-sum', used to create adjectives indicating a tendency or full of a quality. thus, the literal construction "characterized by toil" directly and logically yields the modern meaning of something that involves arduous labor or strenuous effort.

Structure: toil (hard work) + some (characterized by) toil (from old french 'toillier', meaning to struggle or entangle, of latin origin); some (from old english '-sum', an adjective-forming suffix meaning characterized by or productive of).