back door

English definition

noun

1. a secret or underhand means of access (to a place or a position)

   • He got his job through the back door.

   Source: WordNet 3.0

2. an undocumented way to get access to a computer system or the data it contains

   Source: WordNet 3.0

3. an entrance at the rear of a building

   Source: WordNet 3.0