Officer to slip and fall (8)
I believe the answer is:
collapse
'fall' is the definition.
(collapse can mean to fall down)
'officer to slip' is the wordplay.
'officer' becomes 'col' (short for colonel).
'to slip' becomes 'lapse' (lapsing is a kind of slipping).
'col'+'lapse'='COLLAPSE'
'and' is the link.
(Other definitions for collapse that I've seen before include "Fall down or lose strength suddenly" , "Abrupt failure of function" , "Fall or disintergrate" , "Go to ruin" , "Fall down unconscious" .)