Acquiescent
/ˌækwiˈesnt/
Definition 1 of 1
Pro Tip 1/3Non-confrontational
Indicates a person who avoids arguing and may give in easily. 
When asked to work overtime again, she was acquiescent, fearing conflict.
Pro Tip 2/3Passive Acceptance
Shows a lack of resistance, even if internally disagreeing with the situation. 
His acquiescent smile hid his true feelings about the new policy.
Pro Tip 3/3Implicit Agreement
Being acquiescent can be mistaken for full agreement, but it could be reluctant consent. 
Her acquiescent nod was taken as approval, though she was not convinced.