busy
Pronunciation: /ˈbɪzi/
adjective ( busier, busiest)
- 1having a great deal to do: he had been too busy to enjoy himself
- occupied with or concentrating on a particular activity or object of attention: the team members are busy raising money
- (of a time or place) full of activity: the busy city streets I’ve had a busy day
- chiefly North American (of a telephone line) engaged.
verb ( busies, busying, busied)
(busy oneself)noun
(also bizzy)

Origin:
Old English bisgian (verb), bisig (noun); related to Dutch bezig, of unknown origin

Spelling rule
If a word ends in a consonant plus -y, change the -y to an -i before adding any ending (unless the ending already begins with an -i):