Guess the pay increase after middle of October (8)
I believe the answer is:
theorise
'guess' is the definition.
('guess'->'theorize' is in my internal thesaurus and 'ize'->'ise')
'the pay increase after middle of october' is the wordplay.
'pay increase' becomes 'rise' (I've seen this before).
'after' says to put letters next to each other.
'middle of' indicates the central letters.
The central letter of 'october' is 'o'.
'rise' after 'o' is 'orise'.
'the'+'orise'='THEORISE'
(Other definitions for theorise that I've seen before include "Express ideas" , "Think up possible explanations" , "Conjecture, hypothesise" , "Form view" , "Form of hypothesis or conjecture" .)