have a go at

1. To attempt to do or undertake something, especially that which is unfamiliar or new. I know a lot of this work is new to you, but just have a go and let me know if you have any questions. I'm having a go at doing my own taxes this year to save on the cost of hiring an accountant. I don't know if I can do it, but, sure, I'll have a go.

2. To physically attack someone. Watch out for that bull in the back field—he'll have a go at you if you get too close. There were a couple of drunkards having a go outside our local pub last night.

3. To criticize, berate, or verbally harass someone at length or with great intensity. My wife had a go at me last night for coming home drunk again. My parents were always having a go when I was a kid—it's no wonder they got divorced.