submissive
Meaning: easily yielding to authority
Usage: The new assistant was too submissive to question even an unreasonable request.
deferential
Meaning: showing respect for another’s authority
Usage: His deferential attitude toward her made her more confident in her ability to run the company.
defer
Meaning: to postpone something; to yield to another’s wisdom
Usage: Ron deferred to Diane, the expert on musical instruments, when he was asked about buying a piano.