rarna -rar- gismu

x1 is natural/spontaneous/instinctive, not [consciously] caused by person(s).

See also rutni, jinzi, nurma, stati.

In notes:

jinzi
x1 (property - ka) is an innate/inherent/intrinsic/natural property/quality/aspect of x2.
nurma
x1 is a rural/rustic/pastoral area of x2; x1 is in the country.
rutni
x1 is an artifact; x1 is artificial; x1 is made/caused by people/se kulnu x2; x1 is man-made.
stati
x1 has a talent/aptitude/innate skill for doing/being x2.
rarckabu
c1=r1 is a quantitiy of/contains/is made of natural rubber from source c2, of composition including c3.
rarji'i
x1=j1 thinks/knows by instinct/feels that x2=j2 [opinion] (du'u) is true about subject/issue x3=j3
rarske
s1 is natural science with subject s2 =r1 with methodology s3.
rarzi'ejva
z1=r1 is a natural right for z1 to do/be z2 (event/state).