1. 非正式地：unofficial 非正式的 | unofficially 非正式地 | unopened 未开放的

2. 非正式的：distances 距离(复数形式) | unofficially 非正式的 | road signs 路标(复数形式)

3. 非公认地：unofficialinformality 非正式 | unofficially 非公认地 | unoiled 未涂油的

4. 非正式地/非公认地：unofficial /非正式的/非官方/非正式/ | unofficially /非正式地/非公认地/ | unoiled /未涂油的/

adv

1. not in an official capacity

e.g. unofficially, he serves as the treasurer

2. without official authorization

e.g. he had made some money on the side

Synonym: on the side