I'm finally leaving Chrome and migrating my workflow to Firefox (which I used years ago). But it feels like Firefox is missing some basic modern functions, I'm having to install lots of extensions to fill the gaps. But this is a big one, not having native Lookup in the right click/context menu. It's clunky and ruins workflow when the only right-click option is to open a generic google search in a completely different tab... considering a dictionary and thesaurus are already designed to pop up in one small unobtrusive space. It is there, I can access it with a 3-finger tap on a trackpad and don't understand why it's not in the FF context menu. I often work on an external monitor/keyboard setup and don't usually have a trackpad available. Please turn this basic utility on. Reading through forums people have been requesting this for years.
Just an fyi, that it might be either accessible via the 3-finger-tab - as already mentioned - or the so called force click: https://support.apple.com/en-us/102309