timid

Adjective

• lacking conviction or boldness or courage
  • faint heart ne'er won fair lady
    

• lacking self-confidence
  • stood in the doorway diffident and abashed
    
  • problems that call for bold not timid responses
    
  • a very unsure young man
    

• showing fear and lack of confidence

Noun

• people who are fearful and cautious
  • whitewater rafting is not for the timid
    

Related words

• Synonyms: 
  faint , fainthearted , faint-hearted , diffident , shy , unsure , cautious
• Antonyms: 
  confident , bold , brave