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.
He called himself a bungler and declined karaoke.
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.
From 不調法 “inexperience, ineptness; discourtesy” and 者 “person.” 調法 historically meant usefulness or convenience, so 不調法 developed senses of being unskilled, inconvenient, or unable to comply, including polite refusal of alcohol or tobacco.