釘是釘，鉚是鉚 [钉－钉－铆－铆]

Jyutping
Pinyin dīng shì dīng , mǎo shì mǎo

Definitions (CC-CEDICT)
  1. lit. a nail is a nail and a rivet is a rivet (idiom)
  2. fig. meticulous
  3. conscientious
  4. unambiguous