From what I understand, I guess its defined as 'unfaithful'. Anyway, How exactly would I use it in a sentence? Somebody asked me what I look for in a girl, and I'm trying to say somebody who won't engage in unfaithful acts. So if I were to use infeditely in place of that, "I don't want a girl who would commit infidelity." see that doesnt sound right... "She commited Infidelity on me." That doesn't sound right either. Sure I can just say 'unfaithful' but I really want to learn how to use this word so I am asking for some assistance. Thank you guys.