Kartikeya vs Karttikeya

Kartikeya and Karttikeya both are nouns.

Word	Noun	Adjective	Verb	Adverb
Kartikeya	Yes	No	No	No
Karttikeya	Yes	No	No	No

As nouns, Kartikeya and Karttikeya are synonyms defined as:

Kartikeya and Karttikeya: Hindu god of bravery; Hindu god of war; commander-in-chief of the army of the gods; son of Shiva and Parvati

Other synonyms of Kartikeya include Skanda.

Kartikeya (noun)	Karttikeya (noun)
Hindu god of bravery; Hindu god of war; commander-in-chief of the army of the gods; son of Shiva and Parvati	Hindu god of bravery; Hindu god of war; commander-in-chief of the army of the gods; son of Shiva and Parvati