落屎馬 [－－马]

Jyutping lok6 si2 maa5
Pinyin luò shǐ mǎ

Definitions (Wiktionary)
  1. noun, Min-Nan
    a horse with diarrhea
  2. noun, Min-Nan
    good-for-nothing; useless person
    (syn.) 饭桶, 飯桶