ありがた迷惑 (ありがためいわく, arigata meiwaku) is an advanced Japanese word that means “unwelcome favour”: it is arigata-meiwaku if someone does you a favour, but you find it unpleasant and rather annoying. It is usually used to describe someone’s act (e.g. cleaning your room, giving you advice, making cakes for you) which they thought you would like, but in fact you didn’t.
The word consists of the two components “ありがた (arigata)”, short for “ありがたい (helpful)”, and “迷惑” (めいわく, meiwaku), meaning “nuisance/annoyance”.
Synonym: お節介 (おせっかい, Osekkai)
“お節介 (おせっかい, osekkai)” is a synonym of ありがた迷惑 and means “to meddle in other people’s affairs and give an unwelcome favour to them”. It is used either as a noun or verb (お節介する). The major difference between ありがた迷惑 and お節介 is that while ありがた迷惑 describes the act with some irony (i.e. “unfavourite favour”) , お節介 describes your feeling of saying “That’s is none of your business”.
My girlfriend kindly cleaned my room, but that was honestly an unwelcome favour because now I don’t know where all my stuff is.
My mom often sends me lots of snacks, but that is an unwelcome favour because they are not my favourite.
Synonyms: お節介 (to meddle in other people’s affairs and do an unwanted favour)
Synonyms in English: an unwanted favour, white elephant
Related words and phrases: ありがたい (helpful, something one appreciates), ありがとう (Thank you)