The most common and most likely answer to this crossword clue is the 8 letter word HERMETIC
I've seen this crossword clue in The Guardian
H
E
R
M
E
T
I
C
More clues leading to the result HERMETIC
- Adopting leader in Mephistopheles, apostate completely isolated
- Obscure rich meet in new order
- Religious rebel keeping mass occult
- Her mobile primarily has call-back locked
- Island with revolutionary name impervious to external influence?
- The woman’s satisfied if coming first, being completely tight
- Such a seal disguising the crime
Buddy explains!
The straight part
We know that "completely tight" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case completely tight = hermetic.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 HERMETIC mean?
HERMETIC adjective- (chiefly with capital initial) Pertaining to Hermes Trismegistus or the writings attributed to him.
- Pertaining to alchemy or occult practices; magical, alchemical.
- Hermetically sealed.
- Isolated, away from outside influence.