to hide, to conceal oneself, to take cover...

to hide, to conceal

anonymity, using an assumed name

shelter, shield, hide

concealment (esp. of wrongdoings or criminals), sheltering, harboring

hiding, concealment

to shelter (e.g. a fugitive), to harbour, to harbor...

to shelter (e.g. a fugitive), to harbour, to harbor...

ad hoc group formed to commit crimes

concealment, shelter, harboring...

diving under cover and hiding

anonymity

anonymization (of data), anonymisation

anonymous FTP

anonymous criticism

anonymous partnership, silent partnership, anonymous association

anonymous shipping

request to remain anonymous, name withheld by request

hider, person in hiding

secret name, code name

confidentiality, secrecy

to conceal, to keep secret, to cover up

anonymous textboard

concealed materials

privilege (e.g. "attorney-client privilege")

to shelter a criminal

(crime of) harboring a fugitive (harbouring)