The word Castic is misspelled against Caustic, meaning "biting sarcastic"
-->
Word contains consecutive vowels 'AU' in between alphabets c & stic is misspelled as 'A' as letter 'U' is phonetically ignored
Wrong Spelling:  c-a-stic 
Correct Spelling:  c-au-stic 
Find more wrongly spelled words of Caustic to spell it well.