A person (most likely a girl because there can man-Ava's) who won't open a Snapchat or a text message for a extended period of time, usually several hours or days because she is afraid it will affect her Snapscore, thus affecting how her current crush sees her. Another term that is widely used for an Ava is doogus.
"God, I wish Samantha would open my text and stop being such an Ava!"