Leo possibly seeing good chieftains travelling around end of Suez (4,2,3,6)
I believe the answer is:
sign of the zodiac
'leo possibly' is the definition.
(leo is a kind of sign of the zodiac)
'good chieftains travelling around end of suez' is the wordplay.
'travelling' indicates anagramming the letters.
'around' is an insertion indicator.
'end of' indicates one should take the final letters.
The last letter of 'suez' is 'z'.
'good'+'chieftains'='goodchieftains'
'goodchieftains' with letters rearranged gives 'signoftheodiac'.
'signoftheodiac' going around 'z' is 'SIGN OF THE ZODIAC'.
'seeing' acts as a link.
(Other definitions for sign of the zodiac that I've seen before include "lion, say" , "house" , "Maybe Leo" , "old Ford car's indicator?" , "Scorpio maybe" .)