Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
1. annexus (adn-), a, um, Part. of annecto.
* 2. annexus (adn-), ūs, m. [annecto], a tying or binding to, a connection: Cremona annexu connubiisque gentium floruit, Tac. H. 3, 34.