The phrase "pillar of Islam" refers to the fundamental religious obligations that are considered central to the practice of Islam. These pillars consist of the declaration of faith in the oneness of Allah, performing five daily prayers, giving charity to those in need, fasting during the month of Ramadan, and making a pilgrimage to Mecca at least once in a lifetime for those who are physically and financially capable. Synonyms for the phrase "pillar of Islam" might include "essential Islamic practices", "foundational religious obligations", "core tenets of Islam", or "primary Islamic duties". These synonyms help to convey the significance of these practices in the life of a Muslim and emphasize their importance in the Islamic faith.