CTRL-Click Lookup 'word' is not behaving as expected suggesting spellcheck.net

Suggest the User ( you ) start with Points 1 to 4 and then Test

Still having issues, move onto Steps 5 and 6 and Test Again

Still no resolve - move onto Step 7 and follow instructions therein 

1 - Restart in Safe Mode. This will perform a Disk Repair, clear cache files and only load Apple Software, extensions and fonts. The boot up will be slow and can take some time - Normal.

2 - Safe Mode will also eliminate Third Party Software, extensions and drivers from loading. It will only load the Minimum amount of Core Apple Processes to allow the the computer to function at a reduced Level of Performance 

3 - Does the issue present in this mode ?

4 - Sometimes a Safe Boot followed by a Normal Boot will just put things right.

5 - If not - there could be something in the main User Account playing up. To further isolate this - Set up users, guests, and groups on Mac. Then log out of the Main User account and log into the dummy account and test again if the issue persists.

6 - If the issue is present in the dummy account - then, this appears to be a System Wide issue on the computer.

7 - Download the Application Etrecheck directly from the Developer.

This is a Diagnostic Tool that makes no changes to the computer.

It makes a coherent and readable inventory of both the Hardware and Software used on the computer 

The application is free or paid from added features. 

The Report will Not Reveal Any Personal Information. 

Post back the Full Report - copy and paste - >>>> using the Additional Text Icon ( 3rd Icon to last ) <<<<

This appears to be coming from https://www.grammarly.com/

Is this Application OR Safari Extension Installed on this computer ?

From your big Image, in original posting above, with the url spellcheck.net

In which case, some how, either the User has Downloaded or Enabled this spellcheck.net to be configured as the Default Spell Checker on this computer

I never expected the 'Look Up' function to be leaving my Mac.

Look Up uses several sources beyond your Mac. It is not a spell checker, so since it couldn’t figure out the misspelling, I imagine it provided what it thought might be useful.

I believe you can limit the sources in System Settings, but I’m not at a Mac to try to find the settings.

Have looked at the Report and find No Abnormal Applications that would account for the behaviour

Interestingly, when I now, Control Click Reconcialtion from very First Image above I now get as per image below

Notice the Mis-Spelling

iwaddo wrote:

OK, so have you been able to reach a conclusion?

No, as this machine under normal word lookup will bring up the Expected Builtin Dictionary lookup

Further testing indicates this word spelt in this way reconcialtion also behaves the same on my iMac. If I disconnect from wifi I get a word not found error. I never expected the 'Look Up' function to be leaving my Mac.

Thank you for your help.

Thank you for the Report. 

We will dissect it in detail. 

Will get back to you shortly