I, for example, have unpaid bill that five pounds should cover? (5)
I believe the answer is:
vowel
'i for example' is the definition.
(I is a vowel)
'have unpaid bill that five pounds should cover?' is the wordplay.
'have unpaid bill' becomes 'owe' (to owe is to have a bill that needs paying).
'that five pounds' becomes 'VL' (Roman numeral for five plus L which can mean pound).
'should cover?' is an insertion indicator.
'owe' going into 'vl' is 'VOWEL'.
(Other definitions for vowel that I've seen before include "Kind of letter of the alphabet" , "A, E, I, O or U" , "A or e, say" , "Possibly a" , "Not a consonant" .)