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

• ouzel
• ouzo
• OV
• oval
• oval kumquat
• Oval Office
• oval window
• oval-bodied
• oval-fruited
• oval-shaped
• ovalbumin
• Ovalipes
• Ovalipes ocellatus
• ovarian
• ovarian artery
• ovarian cyst
• ovarian pregnancy
• ovarian vein
• ovariectomy
• ovaritis
• ovary
• ovate
• ovate leaf
• ovation
• oven