a humorous way of saying that somebody lacks money; literally 'lacking the element of water'
Definitions (粵典–words.hk)
語句
窮;迷信嘅講法,認為五行缺水嘅人注定命窮 to be in need of money; to be poor; literally: missing the element of water (water is one of the five basic elements in the Chinese understanding of nature)
「我呢期五行欠水。」「你不嬲都欠㗎啦。」
「我呢期五行欠水。」「你不嬲都欠㗎啦。」
ngo5 ni1 kei4 ng5 hang4 him3 seoi2. nei5 bat1 lau1 dou1 him3 gaa3 laa1 "I've been in need of money lately." "I think that's been the case for a long time."