1. Hard to defeat
   "an unbeatable ball team" 
2. Incapable of being overcome or subdued
   - invincible, unvanquishable

See also: unconquerable, unstoppable

• wild rape
• wild raspberry
• wild red oat
• wild rice
• wild rosemary
• wild rye
• wild sage
• wild sarsaparilla
• wild sarsparilla
• wild senna
• wild sensitive plant
• wild service tree
• wild sheep
• synovial membrane
• synovitis
• synovium
• synsemantic
• synset
• syntactic
• syntactic category
• syntactical
• syntactically
• syntactician
• syntagm
• syntagma