Basically, a friend who is very insistent/opinionated commented on my use of the word 'of' in this sentence: Rom’s hand slid it’s grasp of the man’s arm. He's saying that it isn't 'of' but should be 'off'. Now, I agree that that is a valid word to use, but 'of' works as well. Am I wrong in this? I'm certain I've seen it written that way, and it doesn't make any lack of sense in either context to me.
I have to side with your friend I'm afraid. Sorry. Are you trying to say Rom's grasp of the man's arm slid?
Well, the man is doing something a little bit sickening because he doesn't know any different. So he had gripped it previously, and now his hand has slid off as he realised that. I don't know, I'm sure I've seen it used that way. For example, 'His hand slid it's grasp of the sword hilt as he fell to the ground." Either way, if it's not correct I'll change it.
Rom’s hand slid it’s grasp of the man’s arm. Yeah... that's a construction I would not go with. Hand is the actor, slide is the verb, grasp is the direct object, but it feels logically like slide is being used to mean cast off or lose or rid and in this construction it's just too far from the mark. @SethLoki gives the better, clearer choice. Otherwise, consider trading slide out for a different verb.
Couldn't it be rearranged to something like "The man's arm slipped from Rom's grasp"? Or am I missing the context here?
I agree with the gist of the advice above. The problem you've got is that your construction seems to give agency to Rom's hand as if it's the hand that's directing the action, where I guess you mean for Rom to be performing the action (whether intentionally or not). Also, as it stands, your sentence seems to be incomplete. For example: I slid my grasp of the sword hilt up a hand's breadth towards the pommel. Do you see what I'm driving at? Rom’s hand slid its grasp of the man’s arm up towards his elbow. But we still have the problem of the hand having agency. I'm inclined to agree with your friend. I guess you mean for us to visualize something closer to: Rom’s grasping hand slid off the man’s arm.
Although I have already changed it to off, how about: Rom slid his grasp of the man's arm as he, etc.
Not slid as in slippery, as in his hand relaxed as he realised he didn't need to grip it as he was, so his hand naturally slipped off.
Wish I could help but when I look at that sentence I get movement sickness.... The sentence looks like it's trying to be all over the place and only makes sense to me when I really try to focus on it. To answer your question to the best of my ability "off" works better and "of" makes no real sense. I personally would just rewrite the whole sentence into something smoother and easier for people to read.
Essentially yes, initially he gripped his arm to stop him from doing something, although good natured, was grotesque. Once he understood that the man did not understand the weight of his actions, he relaxed his grip and his hand slid off the man's arm naturally, as opposed to forcefully by the other man.
Where did he slide it? Your construction is still crying out for a direction at the end. The thing is, as others have pointed out above, you'd be better off trying to simplify the sentence. You started with the (with 'of' corrected to 'off'): Rom’s hand slid it’s grasp off the man’s arm. But maybe you should shoot for something closer to this: Rom's stopped grasping the man's arm. Or even this: Rom let go of the man's arm.
Rom's hand absently slid from its grasp of the man's arm. I definitely do not like the use of "of" in your sentence. I think that your friend was correct in his/her critique. It just does not sound right.