Wing it
Definition 1 of 1
Pro Tip 1/3Spontaneity
Wing it implies a spontaneous, on-the-spot action without prior preparation. 
We had no guidebook, so we decided to wing it and explore the city.
Pro Tip 2/3Informal
The phrase 'wing it' is informal and best used in casual conversation. 
I'm not sure what questions they'll ask, but I'll just wing it.
Pro Tip 3/3Uncertainty
Using 'wing it' often indicates a situation where the outcome is uncertain. 
The job interview was today? Guess I'll have to wing it and hope for the best.