one guess
Giving someone one guess of the answer to a question, commonly an obvious answer.
Rizzo: What's up, Kenick?
Kenickie: One guess.
Rizzo: You got a lot to offer a girl. Kenickie: Yeah, you know it.
Kenickie: One guess.
Rizzo: You got a lot to offer a girl. Kenickie: Yeah, you know it.