noun + masu-stem compound (嘘つき)

A productive Japanese noun-formation pattern: noun + masu-stem of a verb produces a new noun denoting an agent or product of the action — 嘘つき ('liar' = lie + tell), 落書き ('graffiti' = drop + write), 物書き ('writer' = thing + write), 早起き ('early riser' = early + get up), 大酒のみ ('heavy drinker'), 力持ち ('strongman'), 物知り ('know-it-all'). The noun specifies what the action is on; the verb-stem nominalizes. One of Japanese's main word-building strategies.