Compounds of 大変

• 大変
  (adv) (1) very
  greatly
  (adj-na,n) (2) immense
  enormous
  great
  (3) serious
  grave
  dreadful
  terrible
  (4) difficult
  hard
  (5) (arch) major incident
  disaster
  (P)
• 大変化
  (n,vs) major change
  major transformation
• 大変革
  (n) revolution
  cataclysm
  drastic change
• 大変身
  (n,vs) makeover
  major change
• 結構大変
  (exp) quite a chore
  not that easy
  fairly difficult
• 大変お世話になりありがとうございました
  (exp) thank you for all your hard work
• この度は大変お世話になりありがとうございました
  (exp) thank you for all your hard work
• このたびは大変お世話になりありがとうございました
  (exp) thank you for all your hard work