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Someone who commonly sips from a straw, often protruding from a beverage of various liquids.

One who sips sinisterly is considered extremely dangerous, take caution when approaching one in the wild.
man 1: dude, what is that thing?
man 2: i don't know, it looks pretty sinister
man 1: what is it sipping?!?
man 2: oh my word, it's a sinister sipper! run!!
by thesipper12345 April 06, 2012