The keyword "straight-jacket" has mysteriously disappeared,

@keyword_expert​ Straightjacket has disappeared as well.

@adrian​ Yes, but as @Peter_pbn pointed out, "the correct spelling is straitjacket." 

It is possible that someone else manually edited all the instances of "straight-jacket" and/or "straightjacket" into "straitjacket." It wasn't me, though. And if that did happen, it would have been prior to January, or else I would have included those keywords as part of my proposal to merge into "straitjacket."

@keyword_expert​ Ah. I didn't catch the spelling differences as there are still many keywords with "straightjacket" or "straight jacket".

@adrian​ Yeah, those should probably be cleaned up as well.  

It is possible that the change(s) from the "straight" spellings to the "straitjacket" spelling might also have come from one my mass merger lists, but I can't find any record of that.  I know I didn't make any manual edits to change that spelling.