1. Lacking interest, significance or impact
   "jejune novel";
   - insipid, wishy-washy [informal]
    
2. Displaying or suggesting a lack of maturity
   "jejune responses to our problems";
   - adolescent, juvenile, puerile
    
3. Of insufficient quantity to meet a need
   "the jejune diets of the destitute";
   - inadequate, poor, short

See also: deficient, immature, insufficient, lame, lameo [informal], meh [informal], uninspiring, uninteresting

Encyclopedia: Jejune