Choose the perfect synonym or antonym for the word

Principal

/ˈprɪnsəpəl/

The chief person in charge of a school, or a sum of money invested or loaned, on which interest is paid.

Synonyms:

"Exactitude is the principal qualification required in an intendant of finances."

I am not the principal here.

Isn't Quilp," she says, "our principal support?"

From late Middle English, originating from the Old French principal and Latin principalis, from princeps meaning first in order or chief.

21 mentions per 1 million words

Often

Hint: Frequency according to COCA