One who shouldn't be driving

• One on the phone, often
• One having a silent chat
• One who might type "OMG" or "CYA"
• Today's teen, often
• You shouldn't be a driver and this simultaneously

Wiktionary Word definitions in Wiktionary
n. 1 One who texts; one who sends text messages. 2 ''(Australia'') a marker#English, felt-tipped pen

Wikipedia Word definitions in Wikipedia
Texter is a surname. Notable people with the surname include: Gilda Texter (born 1946), American costume designer John Texter (born 1949), American engineer