The most common and most likely answer to this crossword clue is the 4 letter word BUOY
I've seen this crossword clue in The Guardian
B
U
O
Y
More clues leading to the result BUOY
Buddy explains!
The straight part
We know that "cardinal as an example" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cardinal as an example = buoy.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 BUOY mean?
BUOY noun- A float moored in water to mark a location, warn of danger, or indicate a navigational channel.
- A life-buoy; a life preserver.
- To keep afloat or aloft; used with up.
- To support or maintain at a high level.
- To mark with a buoy.
- To maintain or enhance enthusiasm or confidence; to lift the spirits of.