I-adjective (keiyoushi)
dizzying (speed, changes, etc.); rapid; drastic; bewildering; hectic; bustling (e.g. world)
Usually written using kana alone
ここ数日天気がめまぐるしく変わっている。We've had all kinds of weather over the past few days.
Also written 目紛しい【めまぐるしい】