jesni -jes- gismu

x1 is a needle [pointed shape/form, not tool] of material x2.

See also konju, pijne, jipno, kinli.

In notes:

jinku
x1 is a vaccine/immune-system stimulant protecting x2 against disease x3 introduced by method x4.
jipno
x1 is a tip/point/vertex/extremity/end [0-dimension shape/form] on object x2 at locus x3.
kinli
x1 is sharp/keen at locus x2.
konju
x1 is a cone [shape/form] of material x2 with vertex x3.
pijne
x1 is a pin/peg (needle-shaped tool) for fastening to/piercing x2, of material/properties x3.
crogle
g1 practices sadomasochism with g2=c1 with pain at locus c2.
jeske'a
x1 is a needle eye of needle x2
jespezli
p1=j1 is a needle [pointy leaf] of plant j2.
jesycilta
c1 is barbed wire.
jesystani
s1 is a thorn of plant/species s2