Fraternization

Definitions

1. The act of fraternizing or uniting as brothers.
   countable, uncountable
2. Having a friendly relationship with the enemy.
   countable, uncountable
3. any type of disallowed, supposedly unethical and unprofessional, social or intimate contact between employees, especially between different gender, class or rank.
   US, countable, derogatory, uncountable

Equivalents

CEFR level