expression, noun which may take the genitive case particle 'no', noun
secondary; of secondary importance
Used to describe something that is not the top priority; often appears in the pattern ～は二の次だ or ～を二の次にする.
彼にとって仕事は二の次で、家族が一番大切だ。
For him, work is secondary; family comes first.
It's dangerous to keep working while putting your health second.