The unobservant use the wrong runway (6)

I believe the answer is:

unwary

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'the unobservant use the' is the definition.
I can't judge whether this definition defines the answer.

'wrong runway' is the wordplay.
'wrong' is an anagram indicator.
'runway' is an anagram of 'UNWARY'.

Can you help me to learn more?

(Other definitions for unwary that I've seen before include "Careless" , "Not alert to danger, gullible" , "Runway (anag)" , "Off guard" , "Not alert or suspicious" .)

I've seen this clue in The Globe and Mail.

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