The most common and most likely answer to this crossword clue is the 7 letter word TALLEST
I've seen this crossword clue in The Guardian
T
A
L
L
E
S
T
More clues leading to the result TALLEST
- Everything in trial is unbelievable in the extreme
- Most unbelievable to be wholly involved in trial
- Highest of everybody in exam
- 100% in exam is most unlikely
- Everything in game is most implausible
- Most remarkable everyone’s taking part in challenge?
- Most difficult of everything in the exam
- Looking back, trade in bric-a-brac most unlikely
- Everyone enters exam — I’m head and shoulders above the rest?
- Most remarkable trial absorbs everyone
Buddy explains!

The straight part
We know that "Most remarkable" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case most remarkable = tallest.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 TALLEST mean?
TALLEST adjective- (of a person) Having a vertical extent greater than the average. For example, somebody with a height of over 6 feet would generally be considered to be tall.
- (of a building, etc.) Having its top a long way up; having a great vertical (and often greater than horizontal) extent; high.
- (of a story) Hard to believe, such as a tall story or a tall tale.
- (of a cup of coffee) A cup of coffee smaller than grande, usually 8 ounces.
- Obsequious; obedient.
- Seemly; suitable; fitting, becoming, comely; attractive, handsome.
- Bold; brave; courageous; valiant.
- Fine; proper; admirable; great; excellent.