a slacker; those who doesn't know how to adapt to changing circumstances and are set in their ways (literally: a squared wood); describes someone who is very passive
Definitions (粵典–words.hk)
名詞、俚語
圓形嘅木推一下就碌好順，但四方形嘅木頭就要用力推先識碌一下，用作形容被動懶散嘅人 lazy man.literally: square lump of wood