WordWeb Online

1. Set in a rigidly conventional pattern of behaviour, habits, or beliefs
   "obsolete fossilized ways"
   - fossilised [Brit], ossified

1. Convert to a fossil
   "The little animals fossilized and are now embedded in the limestone"
   - fossilise [Brit]
    
2. Become mentally inflexible
   - fossilise [Brit]

See also: fossil, fossilization, inflexible

Type of: age, convert, get on, maturate, mature, senesce

Encyclopedia: Fossilize