Leave out some breakfast -- I'm officially rising (4)
I believe the answer is:
omit
'leave out' is the definition.
('omit' can be a synonym of 'leave out')
'some breakfast i'm officially rising' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'rising' says the letters should be written in reverse (going up in a down clue).
'timo' is hidden within 'breakfast im officially'.
'timo' in reverse letter order is 'OMIT'.
(Other definitions for omit that I've seen before include "Skip" , "Exclude - neglect" , "Exclude; forget to include" , "Leave out or exclude" , "Fail to include" .)