unassertive
/ˌʌnəˈsɜːrtɪv/
adjective
- Not having or showing a confident and forceful personality; shy or passive.
- The puppy was unassertive, always hanging back while the other dogs played.
- He was too unassertive to ask for a raise, even though he deserved one.
- Her unassertive nature made it hard for her to speak up in meetings.