IPA: /ˌʌn.əˈsɜː.tɪv/
KK: /ʌnəˈsɜrtɪv/
Someone who is not confident in expressing their opinions or needs, often being quiet or reserved in social situations.
She was unassertive in the meeting, rarely speaking up to share her ideas.
Unassertive → It is formed from "un-" (meaning not) and "assertive" (from Latin "assertivus", meaning inclined to assert or affirm). The word "unassertive" means not inclined to assert oneself or lacking in confidence to express opinions or desires.
Think of 'not' ('un-') being added to someone who is 'assertive' — this helps you remember that 'unassertive' describes a person who does not confidently express their thoughts.