This is the 4050th most frequent French word.
clandestinement
Secretly or covertly.
In this sentence, 'clandestinement' conveys the means of sending the documents, highlighting the secrecy involved.
Les documents ont été envoyés clandestinement par un messager.
The documents were sent clandestinely by a messenger.
The word 'clandestinement' is used to indicate an action carried out secretly or stealthily.
Il est entré clandestinement dans le bâtiment.
He entered the building clandestinely.
Here, 'clandestinement' emphasizes the secretive nature of the meeting, away from public attention.