Troublesome means causing difficulty over and over again. A troublesome knee, a troublesome tenant, troublesome details.
The over and over is the whole content: a troublesome knee is one that keeps going wrong rather than one that hurts once. It is mild, which makes it useful for complaining about something without sounding as though you are.
1adjectivetroublesomeCausing difficulty over and over again.
“The old car has been troublesome all year, breaking down every few weeks.”
troublesome is a quality.
Trouble plus -some, from Old French torbler, from Latin turbidus, confused or disturbed.
Latin
turbula — disorderly group, a little crowd or people
Vulgar Latin
*turbulō
Old French
troubler
Middle English
troublen
English
trouble
English, today
troublesome
Built from
From trouble + some. trouble Verb is from Middle English troublen, trouble, borrowed from Old French troubler, trobler, trubler, metathetic variants of tourbler, torbler, turbler, from Vulgar Latin turbulō, from Latin turbula (“disorderly group, a little crowd or people”), diminutive of turba (“stir; crowd”). The noun is from Middle English trouble, troble, from Old French troble, from the verb.
Etymology from Wiktionary, CC BY-SA