1. Not easy to understand or use
   "user-unfriendly" 
2. Not disposed to friendship or friendliness
   "an unfriendly coldness of manner"; "an unfriendly action to take" 
3. Not friendly
   "an unfriendly act of aggression"
   - inimical 
4. Very unfavourable to life or growth
   "the unfriendly environment at high altitudes"
   - hostile, uncongenial

See also: beetle-browed, chilly, cool, friendliness, hostile, incompatible, inhospitable, scowling, uncongenial, uncordial, unfriendliness, unneighborly [US], unneighbourly [Brit, Cdn], unsociable

Antonym: friendly

Encyclopedia: Unfriendly

• footed
• footedness
• footer
• footfall
• footfault
• footgear
• foothill
• foothold
• footie
• footing
• footle
• footless
• footlights
• footling
• footlocker
• footloose
• footman
• footmark
• footnote
• footpad
• footpath
• footplate
• footprint
• footprint evidence
• footrace