head to head 是交头接耳,是两个亲密的好友 窃窃私语的意思
face to face 是面对面,当面
eg.The two little girls are chatting head to head in class.
It is hard to make a deal on the phone.Let's talk face to face.
不懂追问,请及时采纳!别的类似的词还有哪些？hand by hand , side by side, shoulder to shouldereye to eye (眼对眼，心有灵犀)