hadj vs pilgrim's journey

hadj and pilgrim's journey both are nouns.

Word	Noun	Adjective	Verb	Adverb
hadj	Yes	No	No	No
pilgrim's journey	Yes	No	No	No

As nouns, pilgrim's journey is a hypernym of hadj; that is, pilgrim's journey is a word with a broader meaning than hadj:

hadj: the fifth pillar of Islam is a pilgrimage to Mecca during the month of Dhu al-Hijja; at least once in a lifetime a Muslim is expected to make a religious journey to Mecca and the Kaaba
pilgrim's journey: a journey to a sacred place

Other hypernyms of hadj include pilgrimage, pillar of Islam.

hadj (noun)	pilgrim's journey (noun)
the fifth pillar of Islam is a pilgrimage to Mecca during the month of Dhu al-Hijja; at least once in a lifetime a Muslim is expected to make a religious journey to Mecca and the Kaaba	a journey to a sacred place