King's back at Irish republic since 1948 (6)
I believe the answer is:
israel
'republic since 1948' is the definition.
(I've seen this in another clue)
'king's back at irish' is the wordplay.
'king's' becomes 'lear's' (King Lear).
'back' says the letters should be written backwards.
'at' is a charade indicator (letters next to each other) (I've seen this in other clues).
'irish' becomes 'i' (this might be a standard abbreviation of which I'm unaware).
'lears' written backwards gives 'srael'.
'srael' after 'i' is 'ISRAEL'.
Can you help me to learn more?
(Other definitions for israel that I've seen before include "Zion" , "Eastern Mediterranean country" , "Serial set in Middle East state" , "Lear is to be found in this state" , "Sir, ale is available in the country" .)