Lie about issue over current omission (7)
I believe the answer is:
elision
'omission' is the definition.
(elision is a kind of omission)
'lie about issue over current' is the wordplay.
'about' indicates anagramming the letters.
'issue' becomes 'son' (issue can mean someone's offspring).
'over' indicates putting letters inside.
'current' becomes 'i' (symbol for electric current).
'son' going around 'i' is 'sion'.
'lie' with letters rearranged gives 'eli'.
'eli'+'sion'='ELISION'
(Other definitions for elision that I've seen before include "Omission of a sound in speech" , "Omission (from a book, etc)" , "Omission (of a syllable)" , "Dropping of vowel" , "Dropping a letter" .)