adj.无自信的；客客气气的；羞怯的
He was too diffident to express his opinion. 他太不自信，不敢发表自己的见解。
She is diffident about expressing her opinions. 她怯于表述自己的意见。
He has a politely diffident manner. 他的态度是客气中带有羞怯。
adv.胆怯地；羞怯地
