談空說有

From Su Shi's poem 《寄吳德仁兼簡陳季常》 ("Poem sent for Wu Deren and for Chen Jichang as well") (translation from Qiu, 2013^[1]):

• 龍丘居士亦可憐，
  談空說有夜不眠，
  忽聞河東獅子吼，
  柱杖落手心茫然。 [Literary Chinese, trad.]

  ---

  龙丘居士亦可怜，
  谈空说有夜不眠，
  忽闻河东狮子吼，
  柱杖落手心茫然。 [Literary Chinese, simp.]

  Lóngqiū jūshì yì kělián,
  Tán kōng shuō yǒu yè bùmián,
  Hū wén hédōng shīzǐ hǒu,
  Zhù zhàng luò shǒu xīn mángrán.

  The lay practitioner of Dragon Hill is also pitiful,
  he stays up discoursing on emptiness and fullness all night long.
  Suddenly he hears a lion’s roar from east-of-the river,
  the cane drops from his hand, he is at a loss.

Originally meaning "to discuss non-existence and existence → to discuss Buddhist doctrines", it then underwent semantic pejoration to "gossip, idle talk, empty talk".

談空說有

1. gossip, idle talk, empty talk