What is the word 'fantastic' when translated from English to Japanese?
There are several similar words, two of the most common being
Sugoi (which I tend to translate as 'Super') and Subarashii (which
is usually translated as 'Wonderful'). Saikō (extend the sound of
the o), which does sound a lot like 'psycho,' could be translated,
'the best.' The Japanese have also borrowed a great deal of English
words, so it would not be uncommon to hear 'Ameejingu' (Amazing).
You can just say the adjective itself or put together a complete
sentence like: 1. Sore wa sugoi yo! (That's super cool!) 2. Sore wa
subarashii desu! (That's wonderful!) 3. Anata wa saikō no tomodachi
desu! (You are the best friend ever!)