Awareness of things moving behind one (7)
I believe the answer is:
insight
'awareness' is the definition.
(I've seen this before)
'things moving behind one' is the wordplay.
'moving' indicates an anagram (letters are moved around).
'behind' says to put letters next to each other.
'one' becomes 'i' (Roman numeral).
'things' is an anagram of 'nsight'.
'nsight' put after 'i' is 'INSIGHT'.
'of' is the link.
(Other definitions for insight that I've seen before include "Awareness" , "Enlightenment" , "Grasp" , "Deep understanding" , "Perceptiveness" .)