The most common and most likely answer to this crossword clue is the 6 letter word LAMMAS
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More clues leading to the result LAMMAS
- Priests outside mark old feast day
- First of month welcomed by priests, old feast day
- Priests holding mass for religious feast
- Starter of mutton scoffed by priests in RC feast once
- Plate full of nuts and fish served in season of August
- Beat graduates one day in August
- Sounds like sheep rump for summer feast!
- Monks consume first meal in Scottish festival
Buddy explains!

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.