I understand that "effective" has also this meaning. But, as I pointed out, is ambiguous, with the "default" meaning being very different (not just subtly) from

I understand that "effective" has also this meaning. But, as I pointed out, is ambiguous, with the "default" meaning being very different (not just subtly) from the intended one. Especially as, in evolutionary biology, and game theory, there is a big topic of investigating how egoistic behaviour may give raise to an altruistic effect. (And of course, the main thing is that adjectives created from nouns are very ambiguous, i.e. effective can mean both "altruism that gives effect" or "altruism that is an effect".)