How do you say reaper in Gaelic?

There isn't a single, universally accepted translation for "reaper" in Gaelic (which encompasses Scottish Gaelic and Irish Gaelic). The best translation depends on the nuance you want to convey. Here are some possibilities:

* For the person who reaps grain: You'd likely use words related to harvesting. In Irish Gaelic, this could be something like buachaill/cailín faoiseamh (harvest boy/girl) or a phrase describing the action, such as duine a ghearrann an arbhar (person who cuts the grain). In Scottish Gaelic, similar phrases would use words like buachaille (boy, herdsman, but could be adapted) and arbhar (grain).

* For the Grim Reaper: This requires a more metaphorical approach. You'd need to choose words suggesting death and reaping souls. There's no direct equivalent. You might use descriptive phrases like an gortaire anam (soul reaper) in Irish, or something similar in Scottish Gaelic that conveys the idea of death taking souls. However, these are constructions, not direct translations.

In short, there's no single word. You need to choose words or phrases based on the *context* of "reaper."