Cutting Through Spiritual Materialism, by Chögyam Trungpa is a book addressing many common pitfalls of self-deception in seeking spirituality, which the author coins as Spiritual materialism. The book is the transcript of two series of lectures given by Trungpa Rinpoche in 1970-71 and is considered one of Trungpa's seminal works by his publisher, Shambhala Publications.
In Psychology Today, Michael J. Formica gives this definition: "Spiritual materialism is that process by which the ego grasps at the accomplishments and progress of the self upon the spiritual path; an act by which its very nature denies the Self." By this Formica means that spiritual materialism is the act of seeking spirituality for the sake of being spiritually accomplished, so that this spirituality acts to secure the ego more, rather than to help see through it, as he explains in the following quote:
As soon as we cast something into a role, as soon as we put a label on it, as soon as we name it and give it life by virtue of our investment (read: ego), we take away all its power and it is nothing more than an event -- it is no longer a spiritual revelation, but simply a material experience. That is spiritual materialism at its peak.