Before I edit this and change lamaism to Vajrayana, I thought I'd check and see if it's derogatory. Is lamaism ever used inside the relevant community or is this a word used by outsiders to distinguish Vajrayana from real Buddhism? If so, it's derogatory and should be fixed unless required for historical context, e.g. the Soviets who were hostile to Buddhism, called it Lamaism.
Observing the tremendous emphasis placed on the guru in the Tibetan Buddhist vajrayana tradition, they have called this not Buddhism but Lamaism. And they make a distinction between Buddhism and Lamaism.
Tibetan Buddhism, also called (incorrectly) Lamaism, branch of Vajrayana (Tantric, or Esoteric) Buddhism that evolved from the 7th century ce in Tibet.