The fourth of July, for people in general (4)
I believe the answer is:
they
'people in general' is the definition.
(I've seen this before)
'the fourth of july' is the wordplay.
'fourth of july' becomes 'y' (fourth letter of the word 'July').
'the'+'y'='THEY'
'for' acts as a link.
(Other definitions for they that I've seen before include "People in general" , "Pronoun for people" , "Pronoun for more than one" , "Those people (vb. subject)" , "Do -- Know It's Christmas (Band Aid)" .)