noun
clumsy person; bungler; untalented person; nondrinker; nonsmoker
A somewhat old-fashioned or self-deprecating term for someone who is inept, lacks social graces, or has no particular skill, especially in performing arts. Can also refer to someone who does not drink or smoke, often in social contexts where that is notable.
彼は自分を不調法者だと言って、カラオケを断った。
He called himself a bungler and declined karaoke.
宴会で不調法者は肩身が狭い思いをすることもある。
At parties, a nondrinker can sometimes feel out of place.
不器用 is a common word for physical clumsiness or lack of dexterity, while 不調法者 is rarer and broader, covering social ineptitude, lack of talent, or abstaining from drinking/smoking.
下手 simply means 'unskillful' at a specific activity; 不調法者 implies a more general ineptness or a person who is out of place.
不調法 (ぶちょうほう) means 'clumsy' or 'inept', from 不 (not) + 調法 (method, manner). 者 (もの) means 'person'. The exact historical derivation is uncertain, but the term is now rare and somewhat dated.