Order fence if it's cost-effective (9)
I believe the answer is:
efficient
'effective' is the definition.
(I know that effective can be written as efficient)
'order fence if it's' is the wordplay.
'order' is an anagram indicator.
'fence'+'if'+'it'='fenceifit'
'fenceifit' is an anagram of 'EFFICIENT'.
'cost' is the link.
I am not very happy about this link. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for efficient that I've seen before include "Effective in doing what is required" , "Effective, competent" , "Working well with little waste" , "Producing results with little waste of effort" , "Performing with little wastage" .)