Get up for an increase in pay (5)
I believe the answer is:
arise
'get up' is the definition.
(synonyms)
'an increase in pay' is the wordplay.
'an' becomes 'a'.
'increase in pay' becomes 'rise' (I am not sure about this - if you are sure you should believe this answer much more).
'a'+'rise'='ARISE'
'for' acts as a link.
Can you help me to learn more?
(Other definitions for arise that I've seen before include "Originate; get up" , "Tower" , "Occur; stand up" , "Emerge" , "W B Yeats: 'I will . . . . . and go now'" .)