Lofty refusal to take a bit of a gamble (5)
I believe the answer is:
noble
'lofty' is the definition.
(similar in meaning)
'refusal to take a bit of a gamble' is the wordplay.
'refusal' becomes 'no' (it's a no).
'to take' means one lot of letters go next to another.
'a bit of a gamble' becomes 'ble' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'no'+'ble'='NOBLE'
Can you help me to learn more?
(Other definitions for noble that I've seen before include "Imposing, magnificent" , "Lord" , "Dignified" , "Maybe count" , "titled person" .)