The most common and most likely answer to this crossword clue is the 5 letter word SUPER
I've seen this crossword clue in The Sunday Telegraph
S
U
P
E
R
More clues leading to the result SUPER
- Fantastic salesperson getting us to the top
- Wonderful agent, American, turning up
- Wonderful agent takes us up
- Top cop having risen in service, free of imperfection
- Wonderful evening meal: one starter of prawns less
- Half-hearted meal is exceptionally good
- Marvellous evening meal down by a piano
- Very nice meal. Only 1 p
- Top cop, one petitioning for retention of power
- Meal reduced by 1p. Great!
Buddy explains!

The straight part
We know that "Lovely" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case lovely = super.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SUPER mean?
SUPER adjective- Of excellent quality, superfine.
- Better than average, better than usual; wonderful.
- Very; extremely (used like the prefix super-).
- Short for superannuation.
- Short for supercomputer.
- Short for superhero.
- Short for superhive.
- Short for superintendent, especially, a building's resident manager (sometimes clarified as “building super”).
- Short for supernaturalist, especially as distinguished from bright.
- Short for supernumerary; specifically, a supernumerary actor.
- Short for supertanker.
- Short for supervisor.
- Short for superhive.
- Short for superimpose.