The Collaborative International Dictionary of English v.0.48:

Jejune \Je*june"\, a. [L. jejunus fasting, hungry, dry, barren,
   scanty; of unknown origin.]
   [1913 Webster]
   1. Lacking matter; empty; void of substance.
      [1913 Webster]

   2. Void of interest; barren; meager; dry; as, a jejune
      narrative.

   3. Juvenile; childish; immature.
      [PJC]

   4. Lacking nutritional value.
      [PJC] - Je*june"ly, adv. -- Je*june"ness, n. --Bacon.
      [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

208 Moby Thesaurus words for "jejune":
   Lenten, Spartan, abstemious, acarpous, ankle-deep, arid, ascetic,
   attenuated, austere, banal, barren, blah, bland, blank, bloodless,
   cadaverous, celibate, characterless, childless, cold, colorless,
   corpselike, cursory, dead, depthless, desert, desolate, dilute,
   diluted, dismal, draggy, drained, drearisome, dreary, dried-up,
   dry, dryasdust, dull, dusty, dwarfed, dwarfish, effete,
   elephantine, emacerated, emaciate, emaciated, empty, empty-headed,
   empty-minded, empty-pated, empty-skulled, epidermal, etiolated,
   exhausted, exiguous, fade, fallow, flat, flavorless, frugal,
   fruitless, gaunt, gelded, gruelly, haggard, heavy, ho-hum, hollow,
   hollow-eyed, impotent, impoverished, inane, indifferent,
   ineffectual, inexcitable, infecund, infertile, innocuous, insipid,
   issueless, knee-deep, leached, leaden, lean, lifeless, light,
   limited, low-spirited, marantic, marasmic, meager, mean,
   menopausal, mild, milk-and-water, miserly, namby-pamby, narrow,
   niggardly, nonfertile, nonproducing, nonproductive, nonprolific,
   not deep, on the surface, pale, pallid, paltry, pappy,
   parsimonious, peaked, peaky, pedestrian, pinched, plodding,
   pointless, poky, ponderous, poor, pulpy, puny, rattlebrained,
   rattleheaded, sapless, savorless, scant, scanty, scatterbrained,
   scrawny, scrimp, scrimpy, shallow, shallow-rooted, shoal,
   shriveled, sine prole, skeletal, skimp, skimpy, skin-deep, slender,
   slight, slim, slow, small, solemn, spare, sparing, spiceless,
   spiritless, stale, starvation, starved, starveling, sterile, stiff,
   stingy, stinted, stodgy, straitened, stuffy, stunted, subsistence,
   sucked dry, superficial, surface, tabetic, tabid, tasteless,
   tedious, teemless, tenuous, thin, trivial, uncultivated, underfed,
   undernourished, unfertile, unflavored, unfruitful, unlively,
   unnourishing, unnutritious, unplowed, unproductive, unprofound,
   unprolific, unsavory, unsown, untilled, vacant, vacuous, vapid,
   virgin, washy, waste, wasted, watered, watered-down, watery, weak,
   weazeny, wishy-washy, withered, without issue, wizened, wooden,
   wraithlike