Tiresome is annoying by repetition. The neighbour telling the same story for the fourth time, a form that asks for your address in three separate boxes, a child asking why long past the point of charm.
It is a mild, slightly old-fashioned word, the complaint of somebody too polite to swear: a tiresome man, a tiresome journey, tiresome paperwork. The trap is the tire sitting inside it. Work that exhausts you is tiring; work that bores and irritates you is tiresome, and they are not the same complaint. British speakers reach for it more than Americans do, and it carries a sigh with it — how tiresome. The adverb tiresomely goes in front of words like predictable, long and familiar.
1adjectivetiresomeAnnoying, especially because it goes on too long or repeats.
“The journey was long and tiresome, with three changes and no seats.”
2adjectiveirritatingOf a person: irritating in a small, persistent way.
“He is a tiresome man who corrects everyone's grammar at dinner.”
Too few real examples of this word to estimate which sense is commonest.
Tiresome is tire plus -some, the old ending that means causing or giving, the same one working inside troublesome, quarrelsome and burdensome. What wears your patience thin, in the older and wider sense of tiring, is tiresome.
Middle English
tiren
English
tire
English, today
tiresome
Built from
From tire + some. tire comes from Middle English tiren. From Middle English tiren, tirien, teorien, from Old English tȳrian, tēorian (“to fail, cease, become weary, be tired, exhausted; tire, weary, exhaust”), of uncertain origin. Possibly from Proto-West Germanic teuʀōn (“to cease”), which is possibly from Proto-Indo-European dews- (“to fail, be behind, lag”). Compare Ancient Greek δεύομαι (“to lack”), Sanskrit दोष (“crime, fault, vice, deficiency”).
Etymology from Wiktionary, CC BY-SA