1. Not able to be counted (e.g. because too many to count) 
2. (grammar) of a word that does not have a plural form

Encyclopedia: Uncountable

• unselfishly
• unselfishness
• unsensational
• unsensible
• unsent
• unsentimental
• unsentimentally
• unserviceable
• unservile
• unset
• unsettle
• unsettled
• unsettlement
• unsex
• unsexed
• unsexy
• unshackle
• unshackled
• unshaded
• unshadowed
• unshakable
• unshakably
• unshakeable
• unshaken
• unshaped