Root ر ج ف(r j f) has 4 unique word forms and appears 8 times in the Quran.

English gloss Tremble, Shake, Shiver

Word Translation Occurrences
ٱلرَّجۡفَةُ the earthquake, the earthquake 8
تَرۡجُفُ will quake, will quake 4
ٱلرَّاجِفَةُ the quaking one, the quaking one 2
وَٱلۡمُرۡجِفُونَ and those who spread rumors, and those who spread rumors 2