One word must serve for anything so big it cannot be counted on a single hand.
Such words serve only to prejudice the reading public (particularly those who don't know anything about flying).
But when a thing grows large and respected, then the small words will no longer serve.
Many words, especially common ones, can serve as multiple parts of speech.
But her words did serve to remind him of his original mission.
Those words could serve as the epitaph of their relationship.
You also seem to believe that in French the word serves equally well for love and politics.
The single word served as a reminder of the true monster he was.
If the same words would serve me twice, I don't have to trouble myself thinking up new ones the second time around.
And his words serve as warning to candidates of both parties.