Backdating itself is not illegal, though a lack of accurate disclosure of it may well be fraud.

虽然缺乏准确一些信息它可能就是欺诈行为，但是期权回溯本身是不违法的。

youdao

Fengling is not the only student to have worked in this decidedly dishonest - though not technically illegal - field.

风铃并不是唯一一个从事这项带有明显欺骗性，但理论上又不违法的工作的大学生。

youdao

Ministers' concerns centre on a number of practices, which, though not illegal, appear contrary to the spirit of the legislation.

ECONOMIST: Social housing

Though not illegal, this does allow corrupt brokers to hide illegal late trades in a batch of otherwise legitimate trades.

ECONOMIST: Today Putnam, tomorrow the rest | The

Doctors can use some organs from donors who have just died, but though the practice is not illegal, there are currently no laws to govern it, leaving some doctors wary of the procedure.

BBC: Pressure for organ donation review