Prepared available set (5)
I believe the answer is:
ready
I believe this clue is a triple definition!
'prepared' is the first definition.
(similar in meaning)
'available' is the second definition.
(similar in meaning)
'set' is the third definition.
(I know that set can be written as ready)
(Other definitions for ready that I've seen before include "Fully prepared" , "rough companion" , "Fully-prepared" , "Willing (to do something), prepare" , "In addition" .)