The most common and most likely answer to this crossword clue is the 5 letter word AEGIS
I've seen this crossword clue in The Daily Telegraph
A
E
G
I
S
More clues leading to the result AEGIS
- Protection say accepted by road workers ultimately
- To start with alibi for example is a defence
- Serviceman in rising tide finds protection
- Serviceman in receding tide finds protection
- Soldier in ebbing sea gets support
- Protection from influenza, eg isolation
- Occasionally take against guard
- Protection regularly taken by American soldiers
- US soldier in ocean capsized, getting protection
- Each returning soldier’s protection
Buddy explains!

The straight part
We know that "Protection" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case protection = aegis.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 AEGIS mean?
AEGIS noun- A mythological shield associated with the Greek deities Zeus and Athena (and their Roman counterparts Jupiter and Minerva) shown as a short cloak made of goatskin worn on the shoulders, more as an emblem of power and protection than a military shield. The aegis of Athena or Minerva is usually shown with a border of snakes and with the head of Medusa in the center.
- Usually as under the aegis: guidance, protection; endorsement, sponsorship.