noun
maudlin drinker; person who cries when drunk
Refers to someone who becomes tearful or sentimental under the influence of alcohol. Often contrasted with 笑い上戸 (a happy drunk) and 怒り上戸 (an angry drunk).
彼は泣き上戸で、お酒を飲むといつも泣き出す。
He's a maudlin drinker; he always starts crying when he drinks.
泣き上戸の人は、普段は明るいのに酔うと涙もろくなる
People who are maudlin drinkers are normally cheerful but become tearful when drunk.
Compound of 泣き (crying) and 上戸 (drinker, from 上戸 'heavy drinker'). The term 上戸 originally referred to a person who drinks a lot, and various prefixes describe the drinker's behavior.