The most common and most likely answer to this crossword clue is the 8 letter word SUNBEAMS
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Buddy explains!

The straight part
We know that "Rays" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case rays = sunbeams.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 SUNBEAMS mean?
SUNBEAMS noun- A visible, narrow, and intense (relative to ambient light) ray of sunlight.
- An item of cutlery or crockery laid out on a table, but not used, and which can be returned to the drawer without being washed.
- Any of various lycaenid butterflies of the genus Curetis.
- Any hummingbird of the genus Aglaeactis.
- The direct rays, light or warmth of the sun.
- A location on which the sun's rays fall.
- Geniality or cheerfulness.
- A source of cheerfulness or joy.
- The effect which the sun has when it lights and warms some place.
- Friendly form of address often reserved for juniors.
- Ironic form of address used to an inferior or troublemaker.
- Used to address someone who has just woken up and/or is very sleepy.