Rest that is initially bred in need (3,4)
I believe the answer is:
lie back
'rest' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.
'that is initially bred in need' is the wordplay.
'that is' becomes 'ie' (short for Latin 'id est', 'that is').
'initially' says to take the initial letters.
'in' indicates putting letters inside.
'need' becomes 'lack' (to lack something is to be in need of it).
The first letter of 'bred' is 'b'.
'ie'+'b'='ieb'
'ieb' put into 'lack' is 'LIE BACK'.
Can you help me to learn more?
(Other definitions for lie back that I've seen before include "lounge?" , "Relax" , "Recline" .)