Regex to find word 1 or word 2 but not word 3

I have the following message:

Apr 12 12:48:02 poe true: sudo: nagios : command not allowed ; TTY=unknown ; PWD=/var/log/nagios;

How do I make a regex that looks for the word Sudo or Command but not to look for the word true? Reason being I have other messages that have just the words sudo and command and i’m not interested in viewing the messages with the combination of those 2 words with that 3rd word. I have so far tried:

1.(?=.*word1)(?=.*word2)
2. word1.*word2

Both of them failed to exlcude the word that I don’t want. Basically I want the resultant set to not consist of those messages that would have word3 along with word1 and word2 but want the resultant set to have either word1 or word2.

Thanks!