"Most of this is done in a clandestine nature, and the specifics are left to negotiation," he said.

Be advised this list may be incomplete due to the clandestine nature of the activities described.

Due to the clandestine nature of these migration flows, however, no official statistics exist.

Because of their clandestine nature, it is impossible to tell how many illegal apartments there are in a given community.

Due to its clandestine nature, the illegal trade is difficult to quantify with any accuracy.

The clandestine nature made such important discoveries look unpatriotic.

But the clandestine nature of such marriages makes reliable statistics unavailable.

The military operations of the Qassem brigades are by nature clandestine.

The clandestine nature of the operation was an added benefit; it even made going to work fun.

The extent of illicit drug use inside prison has been far more difficult to measure because of its clandestine nature.