Long period of time before end of Ramadan (5)
I believe the answer is:
Here is my best explanation:
'long' is the definition.
('yearn' can be a synonym of 'long')
'period of time before end of ramadan' is the wordplay.
'period of time' becomes 'year' (year is a kind of period of time**).
'before' says to put letters next to each other.
'end of' suggests the final letters.
The last letter of 'ramadan' is 'n'.
(Other definitions for yearn that I've seen before include "Have an intense feeling of longing", "Long (for something)", "Strongly desire", "Long - pine", "Have a great longing", "Desire, want", "Curdle", "Pine; long", "Hanker" and "Have a craving".)