What is the meaning of nip and tuck?

noun

• Plastic surgery to remove wrinkles and other signs of aging from your face; an incision is made near the hair line and skin is pulled back and excess tissue is excised.
  • usage: "some actresses have more than one face lift"
  • synonyms: face lift, facelift, lift, face lifting, cosmetic surgery, rhytidectomy, rhytidoplasty

adjective

• Inconclusive as to outcome; close or just even in a race or comparison or competition.
  • usage: "as they approached the finish line they were neck and neck"; "the election was a nip and tuck affair"
  • synonyms: neck and neck, head-to-head

adverb

• Even or close in a race or competition or comparison.
  • usage: "the horses ran neck and neck"; "he won nip and tuck"
  • synonyms: neck and neck, head-to-head