adjective

lacking interest or excitement.

your diet doesn’t have to be dull and boring

uninteresting,boring,tedious,tiresome,wearisome,dry,dry as dust,flat,bland,characterless,featureless,colourless,monotonous,unexciting,uninspiring,unstimulating,lacking variety,lacking variation,lacking excitement,lacking interest,unimaginative,uneventful,lifeless,soulless,insipid,unoriginal,derivative,commonplace,prosaic,run-of-the-mill,humdrum,unremarkable,banal,lame,plodding,ponderous,pedestrian,dull as dishwater,deadly,no great shakes,not up to much,dreich,dullsville,ornery