The most common and most likely answer to this crossword clue is the 6 letter word DAEMON
I've seen this crossword clue in The Daily Telegraph
D
A
E
M
O
N
More clues leading to the result DAEMON
- No honeyed drink brought back or spirit
- No sweet drink served up — one wants spirit
- Revolutionary gnome admired, not entirely an evil spirit
- No strong drink served up as Guardian spirit
- Spirit getting drunk after alcoholic drink returns
- Moaned about guardian spirit
- Spirit available after fermented drink knocked over
- It’s divine being in form — demand regularly to be recalled
- Genius mad woman heads out rambling
- Made befuddled on spirit
Buddy explains!

The straight part
We know that "guardian spirit" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case guardian spirit = daemon.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 DAEMON mean?
DAEMON noun- An evil supernatural spirit.
- A neutral supernatural spirit.
- Someone with great strength, passion or skill for a particular activity, pursuit etc.; an enthusiast.
- A form of patience (known as Canfield in the US).
- Any of various hesperiid butterflies of the genera Notocrypta and Udaspes.
- A process (a running program) that does not have a controlling terminal.