Fuzz finally stops free dope supply — it's put on ice (4-5)

'put on ice' is the definition.
(past tense of 'deep-freeze')

'fuzz finally stops free dope supply' is the wordplay.
'finally' says to take the final letters.
'stops' means one lot of letters goes inside another (stopping can mean blocking a gap).
'supply' indicates anagramming the letters (in a supple way).
The final letter of 'fuzz' is 'z'.
'free'+'dope'='freedope'
'freedope' with letters rearranged gives 'deepfroe'.
'z' going inside 'deepfroe' is 'DEEP-FROZE'.

'it's' is the link.