WordWeb Online

1. Lacking in nutritive value
   "the jejune diets of the very poor"
   - insubstantial
    
2. Displaying or suggesting a lack of maturity
   "jejune responses to our problems"
   - adolescent, juvenile, puerile
    
3. Lacking interest or significance or impact
   "jejune novel"
   - insipid

See also: immature, jejunely, jejuneness, jejunity, uninteresting, unwholesome

Encyclopedia: Jejune