Center letter: h
Outer letter: g i l n t y
Answers (33):
  nightly
  high
  highlight
  highlighting
  highly
  hill
  hilling
  hilly
  hilt
  hinging
  hinny
  hint
  hinting
  hitting
  light
  lighting
  lightly
  lightning
  nigh
  night
  nightlight
  ninth
  ninthly
  thigh
  thin
  thing
  thingy
  thinly
  thinning
  tight
  tightly
  tilth
  tithing