Colleagues using disablist word instead of name, IABU to approach the manager?

[Piplin]

Have name changed.
Not wanting to be professionally offended, but I'm really cringing when a friend and colleague uses the word 'spacker' when referring to another colleague.
The other colleague knows about it and they are really good friends, socialise outside of work etc.
what is disturbing is that there is a girl at work who has a severely disabled child. She has heard them use this term and just shrugged it off, but has been inwardly upset by this. (She told me)
Should I go to the manager about them using this term? Or should I just leave it, safe in the knowledge that these people are just ignorant?

A bit of background info, these are senior members of staff, me and the other girl are not. The senior members of staff are friends with the manager also, so in all likelihood would get back to them what was said by whom.
I am confident that using this word is just a bit of banter between them and they are not intending to insult anyone, least of all the girl with the disabled child.
They are in all other respects nice people.

Serious question to the people on this thread who haven't heard the word before. Would you not make the connection with the term spastic? Have you honestly never heard this word being used in a derogatory way? I'm genuinely surprised that there are people who don't know or can't guess what it means.

I have never heard this word before. I did not make a connection with spastic. As it lacks any "s" or "z" sound it's not obvious (to me) that is what it is referring to. I don't think I have heard anyone use the word "spastic" since I left school in the late 70s other than in the context of calling IBS "a spastic colon".

What I think it might mean if I'd heard it being used would depend on the context, the parties, the tone (affectionate, disparaging, vitriolic) and even considering possibility it is a regional dialect word I didn't know.

Same as Phaedra.

Thanks Phaedra, I guess it's a good thing that its not widely used and understood.

Same as Phaedra too.