uncluttered (adj.)

• austere
• bare
• basic
• chaste
• chipper
• elementary
• essential
• fundamental
• groomed
• homely
• homespun
• homogeneous
• indivisible
• irreducible
• mere
• monolithic
• neat
• orderly
• plain
• primal
• primary
• pure
• severe
• shipshape
• simple
• single
• snug
• spare
• spick-and-span
• stark
• tidy
• trig
• trim
• unadorned
• undifferentiated
• uniform
• well