Good, fertile housing market initially in brief dip (9)
I believe the answer is:
admirable
'good' is the definition.
(thesaurus)
'fertile housing market initially in brief dip' is the wordplay.
'fertile' becomes 'arable' (I've seen this before**).
'housing' indicates putting letters inside.
'initially' suggests taking the first letters.
'in' indicates putting letters inside.
'brief' means to remove the last letter.
The initial letter of 'market' is 'm'.
'dip' with its final letter removed is 'di'.
'm' inserted within 'di' is 'dmi'.
'arable' enclosing 'dmi' is 'ADMIRABLE'.
(Other definitions for admirable that I've seen before include "Splendid" , "Worthy of being held in high opinion" , "Deserving respect and approval" , "Commendable" , "Deserving of esteem" .)