Hujjat (or Hujjah)– sources sent by Allah (SWT) to guide man to the right path by seizing any justification or excuse of a man to continue his routinely invalid practicesperformed prior to the arrival of the Hujjat. These sources include the Messengers, the Holy Prophets (PBUT), the Holy Books, the Infallibles (PBUT), Scholars and Preachers of Islam, Logical Proofs, Wisdom and Intellect, Elected Representatives of the Infallibles etc.

Itmaam e Hujjat(or Itmaam Al Hujjah) / Ihtijaj– the act or proof of seizing the justification of man by a Hujjat sent by Allah (SWT) or through an act of conversation, dialogue, event etc. to stop him continuing his routinely invalid practices; to establish Hujjat on someone or to present a Hujjat in someone’s presence.

Muhaajjah – two people establishing their Hujjaton one another at the same time; both attempt to present their set of proofs to negate each other’s proofs. 

Hajjah –the intention to perform something and also the intention to stop one from performing something else.