Out-of-the-way and Sub-rosa

Out-of-the-way adjective - Different from the ordinary in a way that causes curiosity or suspicion.

Sub-rosa and out-of-the-way are semantically related. In some cases you can use "Sub-rosa" instead an adjective phrase "Out-of-the-way".

Sub-rosa adjective - Designed and carried out secretly or confidentially.

Out-of-the-way and sub-rosa are semantically related. Sometimes you can use "Out-of-the-way" instead an adjective phrase "Sub-rosa".