A Framer is a Mafia role. As a Night Action, they can target a player, causing any Cop investigation on that player that night to incorrectly report a Guilty or Scum result. Note that Sanity overrides a framing; so a Naive Cop would still receive Innocent or Town results on a framed player. Likewise an Insane Cop would get also Town result on a framed player due to their Sanity.
One rare variant of a framer is called a Farmer, where the player permanently changes the perceived alignment of their target - essentially making every player they target a miller. The target may or may not be told of their status change, and the miller status may or may not remain even after the farmer is killed.
Some mods treat a Framer as an investigated-alignment-flipper, causing Town players to appear like Scum, and vice versa. This means that they could target a scumbuddy to make them temporarily function as a Godfather. This is also uncommon, and so this would be made explicit in the Framer role PM if applicable.
The existence and commonness of Framers, as well as their counterpart Godfathers, reinforce why Cops should always think critically regarding their investigation results.