Demanding love, Gloriana entertained by wit (7)
I believe the answer is:
onerous
'demanding' is the definition.
(onerous means difficult or demanding)
'love gloriana entertained by wit' is the wordplay.
'love' becomes 'o' (love means zero in tennis).
'gloriana' becomes 'ER' (Elizabeth Regina, ie Elizabeth I aka Gloriana).
'entertained by' indicates putting letters inside (inserted letters are hosted or entertained).
'wit' becomes 'nous' (both can mean common sense).
'er' placed within 'nous' is 'nerous'.
'o'+'nerous'='ONEROUS'
(Other definitions for onerous that I've seen before include "Burdensome, oppressive" , "Oppressive, difficult to bear" , "Involving a great deal of effort" , "Heavy and hard to bear" , "Burdensome, weighty" .)