Explanation:
A tenet is a principle or rule; a tenant is someone who rents living space. So an important tenet is a rule that really should be followed and an important tenant — maybe someone who pays the rent on time — is one who should get her dripping faucet fixed pronto.

There are a surprising number of examples of misuse among those who really should know better.

Shimshonit writes entertainingly about the issue and offers a possible justification for the mix-up:

The root of both words lies in the Latin word “to hold,” as in “property holding” or “to hold a belief.”

I think the issue is more likely to be the fact that the words sound similar and people who don’t come across them on the page may not realize they are two distinct words.

Follow us on Twitter @tao_of_grammar