to refuse politely to accept or to do sth 谢绝；婉言拒绝 SYN refuse1
I offered to give them a lift but they declined.
我主动提议开车送他们，但他们婉言谢绝了。
~ sth
to decline an offer/invitation
谢绝对方的主动帮助／邀请
~ to do sth
Their spokesman declined to comment on the allegations.
他们的发言人拒绝对这些指控加以评论。