The woman's without Irish letter (5)
I believe the answer is:
hirer
'letter' is the definition.
Although both the answer and definition are singular nouns, I can't understand how one could define the other.
'the woman's without irish' is the wordplay.
'the woman' becomes 'her' (her refers to a woman).
'without' means one lot of letters goes inside another ('without' can be similar in meaning to 'outside').
'irish' becomes 'IR' (abbreviation for Irish).
'her' going around 'ir' is 'HIRER'.
Can you help me to learn more?
(Other definitions for hirer that I've seen before include "Person who obtains use for payment" , "He purchases tempory use of something" , "Person who takes on workers" , "Renter" , "One recruiting workers" .)