low-water mark

English Thesaurus

1. a line marking the lowest level reached (noun.location)

hypernym	:	water line, watermark,
definition	:	a line marking the level reached by a body of water (noun.location)

2. an extreme state of adversity; the lowest point of anything (noun.state)

hypernym	:	adversity, hard knocks, hardship,
definition	:	a state of misfortune or affliction (noun.state)