The most common and most likely answer to this crossword clue is the 5 letter word GREAT
G
R
E
A
T
More clues leading to the result GREAT
- Senior relative finally fuming about a gibe
- Magic / giant
- Fantastic Greek nosh
- Large jar, it's said?
- Tearing about ousting elected chief
- Marvellous young environmentalist’s moving article
- Wonderful place to keep ashes say?
- Impressive kind of force altered rate …
- Looking back, label worn by monarch? Several actually
- Grid said to be fantastic
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 = great.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 GREAT mean?
GREAT noun- A person of major significance, accomplishment or acclaim.
- The main division in a pipe organ, usually the loudest division.
- (in combinations such as "two-greats", "three-greats" etc.) An instance of the word "great" signifying an additional generation in phrases expressing family relationships.
- Relatively large in scale, size, extent, number (i.e. having many parts or members) or duration (i.e. relatively long); very big.
- Of larger size or more importance than others of its kind.
- (qualifying nouns of family relationship) Involving more generations than the qualified word implies — as many extra generations as repetitions of the word great (from 1510s). [see Derived terms]
- (followed by 'with') Pregnant; large with young; full of.
- (except with 'friend' and similar words such as 'mate','buddy') Intimate; familiar.
- Extreme or more than usual.
- Of significant importance or consequence; important.
- (applied to actions, thoughts and feelings) Arising from or possessing idealism; admirable; superior; commanding; heroic; illustrious; eminent.
- Impressive or striking.
- Much in use; favoured.
- (applied to persons) Endowed with extraordinary powers; of exceptional talents or achievements; uncommonly gifted; able to accomplish vast results; remarkable; strong; powerful; mighty; noble.
- Title referring to an important leader.
- Doing or exemplifying (a characteristic or pursuit) on a large scale; active or enthusiastic.
- (often followed by 'at') Skilful or adroit.
- Very good; excellent; wonderful; fantastic (from 1848).
- Intensifying a word or expression, used in mild oaths.
- Very well (in a very satisfactory manner).
- Expression of gladness and content about something.
- Sarcastic inversion thereof.