I recently wanted to state in Esperanto the notion, that
One should introduce new roots into Esperanto only when the same meaning cannot efficiently be expressed using existing roots and affixes.
(emphasis added only to mark the word of interest)
I came up with this partial phrasing:
Oni enkonduku novajn vort-radikojn en Esperanton nur, se ne eblas ____ esprimi la saman signifon kun jam-ekzistantaj vort-radikoj kaj afiksoj.
I didn't know how to express "efficiently" in that context, thus I asked How to express "efficient" in Esperanto?. However, I'm not sure, the general translation of the word would be fit for this context, so I'm asking a separate question here, with the context:
How does one express "to express <something> efficiently" in Esperanto?
What would belong in the gap above?