Fool regularly taking Air Djibouti (5)
I believe the answer is:
idiot
'fool' is the definition.
(synonyms)
'regularly taking air djibouti' is the wordplay.
'regularly taking' indicates alternate letters.
'air'+'djibouti'='airdjibouti'
The alternate letters of 'airdjibouti' are 'IDIOT'.
(Other definitions for idiot that I've seen before include "Steal small amount" , "Charlie" , "Ass, ninny" , "Foolish character" , "Dolt" .)