The most common and most likely answer to this crossword clue is the 10 letter word PHENOMENAL
I've seen this crossword clue in Financial Times
P
H
E
N
O
M
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A
L
More clues leading to the result PHENOMENAL
- Great friend embracing man and women only?
- Remarkable help one man arranged
- Fantastic friend carries “Women Only” sign
- Amazing chap with Roman name visits friend
- Exceptional friend covers bird sign
- . Stunning bird approaches old chaps entertained by lap dance
- Great friend carrying chicken sign
- Great old man left holding “Chicken” sign
- Exceptionally good curiosities left
- Amazing pub by path male individual recalled
Buddy explains!

The straight part
We know that "Fantastic" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fantastic = phenomenal.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 PHENOMENAL mean?
PHENOMENAL adjective- Very remarkable; highly extraordinary; amazing.
- Perceptible by the senses through immediate experience.
- Of or pertaining to the appearance of the world, as opposed to the ultimate nature of the world as it is in itself.