[at the tip of one's tongue] or [on the tip of one's tongue] {adv. phr.}{informal}
1. Almost spoken; at the point of being said.
* /It was at the tip of my tongue to tell him, when the phone rang./* /John had a rude answer on the tip of his tongue, but he remembered his manners just in time./
2. Almost remembered; at the point where one can almost say it but cannot because it is forgotten.
* /I have his name on the tip of my tongue./