1.
tea drinker; teetotaler; person who doesn't drink alcohol
A person who prefers tea or other non-alcoholic beverages over alcohol. An older, somewhat playful expression contrasting with 左党 (a drinker). Derives from the traditional association of the right hand with rice (and by extension, non-alcoholic drinks).
The origin of this term relates to traditional Japanese customs. In the drinking culture, the 左 (left) side was associated with sake (because craftsmen held their chisel in the left hand and their hammer — 槌, homophonous with a sake vessel — in the right), so 左党 came to mean a drinker. 右党 is its counterpart for non-drinkers.
This is an older expression that is still understood but less commonly used in modern casual conversation, where 下戸 (non-drinker) is more typical.