The most common and most likely answer to this crossword clue is the 8 letter word RIGOROUS
I've seen this crossword clue in Financial Times
R
I
G
O
R
O
U
S
More clues leading to the result RIGOROUS
- Very strict set-up or, occasionally, roguish
- Severe operatic prince in endless stir
- Strictly accurate equipment letting in water, though no opening
- Severe Russian seen by river — English river largely
- Spartan outfit not waterproof with cap removed
- Stiff, almost awake, embracing Frankenstein’s helper
- Kindle briefly entertains Russian firm
Buddy explains!
The straight part
We know that "Very strict" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case very strict = rigorous.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 RIGOROUS mean?
RIGOROUS adjective- Showing, causing, or favoring rigour; scrupulously accurate or strict; thorough.
- Severe; intense.