Source : Webster's Revised Unabridged Dictionary (1913)

Jejune \Je*june"\, a. [L. jejunus fasting, hungry, dry, barren,
   scanty; of unknown origin.]
   1. Lacking matter; empty; void of substance.

   2. Void of interest; barren; meager; dry; as, a jejune
      narrative. - {Je*june"ly}, adv. -- {Je*june"ness}, n.
      --Bacon.

Source : WordNet®

jejunely
     adv : in an immature manner; "his teenage son still behaves very
           immaturely" [syn: {immaturely}] [ant: {maturely}]