Prop up; sustain (7)
I believe the answer is:
support
I believe this is a double definition.
'prop up' is the first definition.
(thesaurus)
'sustain' is the second definition.
(I know that sustain can be written as support)
(Other definitions for support that I've seen before include "Maintain, back" , "strengthen" , "Help; bear" , "Shore up" , "second" .)