vapid (adj.)

• airy
• arid
• asinine
• barren
• bland
• blank
• bloodless
• boring
• catchpenny
• changeable
• characterless
• cold
• colorless
• common
• commonplace
• dead
• dilute
• diluted
• dismal
• dreary
• dry
• dull
• dusty
• effete
• elephantine
• empty
• empty-headed
• etiolated
• fair
• fairish
• fatuous
• flat
• flavorless
• flimsy
• foolish
• frivolous
• frothy
• futile
• halfhearted
• heavy
• ho-hum
• hollow
• humdrum
• idle
• inane
• indecisive
• indifferent
• innocuous
• insipid
• irresolute
• jejune
• lackluster
• leaden
• lifeless
• light
• low-spirited
• matter-of-fact
• mediocre
• medium
• middling
• mild
• milky
• moderate
• modest
• mundane
• mushy
• namby-pamby
• neutral
• nugatory
• ordinary
• otiose
• pale
• pallid
• passable
• pedestrian
• plain
• plodding
• pointless
• poky
• ponderous
• prosaic
• prosy
• pulpy
• rattlebrained
• respectable
• sapless
• savorless
• scatterbrained
• shallow
• silly
• slender
• slight
• slow
• so-so
• solemn
• spiritless
• stale
• sterile
• stiff
• stodgy
• stuffy
• superficial
• tame
• tasteless
• tedious
• thin
• tiresome
• tolerable
• trifling
• trite
• trivial
• unembellished
• unflavored
• unimaginative
• unimpassioned
• uninteresting
• unpalatable
• unromantic
• unsavory
• vacant
• vacuous
• vain
• washy
• watered
• watery
• weak
• wearisome
• wearying
• windy
• wishy-washy
• wooden