Allow custom words to be added to the dictionary.
The 'Add to Dictionary' option appears greyed out and disabled when right clicking on a word in Outlook for Mac
Vsevolod Ostapenko commented
Currently spell checker is not getting any feedback from intelligent services. If one is using well known terms from a certain non-too-general-public domain, spell checked complains and tries to "correct" the word it does not understand. Doing smart lookup on a term produces a number of hits, yet, there is no way to propagate the fact that term is valid back to spell checker without going back to red squiggles, right clicking on the term and selecting "add to dictionary".
Intelligent services needs to be smarter, and spell checker as well.
Try typing in term "memoization" in your e-mail.