The most common and most likely answer to this crossword clue is the 4 letter word GLEE
I've seen this crossword clue in Financial Times
G
L
E
E
More clues leading to the result GLEE
- Grand shelter giving rise to delight
- Good area offering shelter leads to joy
- Delight in single entry
- Delight of good sheltered place
- Delight in good shelter
- Leaving Leeds not entirely in high spirits
- Delight at the start of ‘Gimme Shelter’
- Delight in German shelter
- Happiness is having good shelter
- German general’s delight
Buddy explains!

The straight part
We know that "happiness" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case happiness = glee.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 GLEE mean?
GLEE noun- Joy; happiness great delight, especially from one's own good fortune or from another's misfortune.
- Music; minstrelsy; entertainment.
- An unaccompanied part song for three or more solo voices, not necessarily merry.
- To sing a glee (unaccompanied part song).