stodi -sto- gismu

x₁ is constant/invariant/unchanging in property x₂ (ka) in response to stimulus/conditions x₃.

Also stable/consistent/steadfast/firm/steady. See also cenba, stika, stali, vitno, manfo, zasni, tinsa, jdari.

In notes:

cenba: x₁ varies/changes in property/quantity x₂ (ka/ni) in amount/degree x₃ under conditions x₄.
jdari: x₁ is firm/hard/resistant/unyielding to force x₂ under conditions x₃.
manfo: x₁ (object/event) is uniform/homogeneous in property x₂ (ka).
stali: x₁ remains/stays at/abides/lasts with x₂.
stika: x₁ (event) adjusts/regulates/changes x₂ (ka/ni) in amount/degree x₃.
tinsa: x₁ is stiff/rigid/inflexible/resistant in direction x₂ against force x₃ under conditions x₄.
vitno: x₁ is permanent/lasting/[eternal] in property x₂ (ka) by standard x₃ [time-span/expectant one].
zasni: x₁ is temporary/not permanent/expected to change in property x₂ (ka) by standard/expectant x₃.
fausto: x₁ (event) is constant in intensity/amount
jisystota'u: x₁=t₁ is an apron of x₂=j₁=s₁, keeping them clean from contaminant x₃=j₂
stotcu: n₁=s₁ is insatiable in property n₂=s₂ despite input n₃=s₃.
toltinsa: x₁ is flexible/supple/limber/bendable/non-resistant in direction x₂ against force x₃ under conditions x₄.
zvasto: x₁ is immobile/motionless; x₁ does not change in what is it's location
so'au (exp!): subjective number which is constant over time
ziltodi: x₁ is a property of a constant number/amount
stoplin: Name: Mercury