I used Google translate but it shows "Gan", which cannot be its true meaning (it's just the pronunciation). Is that the liquid state of gold? But I think it should be a verb.
淦 (radical 85 水+8, 11 strokes, cangjie input 水金 (EC), four-corner 38119, composition ⿰氵金)
- river in Jiangxi province
- water leaking into a boat
KangXi: page 630, character 25 Dai Kanwa Jiten: character 17667 Dae Jaweon: page 1033, character 5 Hanyu Da Zidian: volume 3, page 1653, character 3 Unihan data for U+6DE6
I know exactly what you mean, as you thought it should be a verb, but I'm not sure if it's possible to explain such a rude slang here.
The true verb which has the same pronunciation as
淦, is a verb involved with sexual harassment or verbal violence. That's all I can tell. Hope you're unintentional.
Edit: Note: The usage is mostly dominant in Taiwan and rarely in other Chinese speaking areas.