fitfully

The adverb 'fitfully' is built upon the 17th-century adjective 'fitful', which literally means 'full of fits'. The core noun 'fit', with its sense of a sudden, paroxysmal attack or period of activity, traces back to Middle English. Its ultimate origin is uncertain but may be connected to Old English. The suffix '-ful', from Old English '-full', denotes 'characterized by'. Therefore, the literal construction 'full of fits' evolved logically to describe actions or processes that occur in irregular bursts, much like the sporadic nature of physical spasms or seizures. Adding the adverbial suffix '-ly' simply grammaticalizes this descriptive quality into a modifier for verbs.

Structure: fitful (irregular) + ly (adverb suffix) - fitful: An English adjective formed from the noun 'fit' (a sudden, short attack or outburst) + the suffix '-ful' (full of). 'Fit' originates from Middle English 'fitte', possibly from Old English. - ly: An English adverb-forming suffix, from Old English '-līce'.