wag

verb6

1. •
   To swing from side to side, as an animal's tail, or someone's head to express disagreement or disbelief.

   • No discerner durst wag his tongue in censure. — 1613
2. •
   To move continually, especially in gossip; said of the tongue.

   • She's a real gossip: her tongue is always wagging.
3. •
   (UK, slang) To play truant from school.

   • They had "wagged it" from school, as they termed it, which..meant truancy in all its forms. — 1901
4. •
   Of the tail (lower order of the batting lineup): to score more runs than expected.

   • The tail wagged.
5. •
   (no longer used) To go; to proceed; to move; to progress.

   • "Thus we may see," quoth he, "how the world wags." — 1598
6. •
   (no longer used) To leave; to depart.

   • I will provoke him to 't, or let him wag. — 1623

noun2

1. •
   An oscillating movement.

   • The wag of my dog's tail expresses happiness.
2. •
   A witty person.

   • Was not my Lord The veryer Wag o'th' two? — 1610

noun3

1. •
   (informal) A wife or girlfriend of a sports star or other celebrity, originally and especially of an association football player.

   • In Wimbledon, the tennis WAGs and - just as excitingly - HABs (Husbands and Boyfriends) have been appearing courtside, enthusiastically cheering on their beloved other halves with a degree of style. — 2006
2. •
   (informal, slang) Acronym of wild-ass guess; a rough estimate.
3. •
   Acronym of women's artistic gymnastics.