Mobile phone user (invariably female) given to inane, loud conversations with other (invariably female) users during which the phrases "Yeah" "I know" and "Did he?" will be uttered metronomically. When not talking on the phone, clackwagglers will be texting. When not texting they can be observed gripping their phones tightly, scanning them every 15 seconds waiting for them to ring.
I boarded the 18.23 train and moved to the quiet car only to be surrounded by a bunch of irritating clackwagglers.