Negative; indicating absence of the condition being tested for.
The rapid COVID test came back neg.
negnoun
A photographic negative, which is an image, usually on a strip or sheet of transparent plastic film, in which the lightest areas of the photographed subject appear darkest and the darkest areas appear lightest.
The photographer developed the negs in the darkroom to create prints.
A negative result on a test, especially an HIV test.
She was relieved when the doctor told her the HIV test was a neg.
negverb
To undermine someone's confidence by giving a back-handed compliment or mild insult, especially as a deliberate flirting tactic.
He tried to neg her by casually mentioning that her shoes looked "comfortable."