It took her a long time to accommodate the Pole (5)
I believe the answer is:
'it took her a long' is the definition.
The definition suggests a singular noun which matches the answer.
'time to accommodate the pole' is the wordplay.
'time' becomes 'ages' (I have seen 'Long time' mean 'ages' so perhaps 'time' could also mean 'ages').
'to accommodate' means one lot of letters goes inside another.
'the pole' becomes 'n' (abbreviation for North, as in North Pole).
'ages' going around 'n' is 'AGNES'.
Can you help me to learn more?
(Other definitions for agnes that I've seen before include "Miss Grey", "Girl's name", "Patron saint of virgins", "St --' Eve, poem by Lord Tennyson", "Tube for cables".)