In Senegal a Moonie mission (5)
I believe the answer is:
alamo
'mission' is the definition.
(famous mission and siege from the Texas revolution)
'in senegal a moonie' is the wordplay.
'in' indicates the answer is hidden within the clue.
'ALAMO' is hidden within 'senegal a moonie'.
(Other definitions for alamo that I've seen before include "Where Jim Bowie died" , "don't forget it!" , "The red planet" , "Scene of massacre in Texas" , "Site of a Texas siege, 1836" .)