[/nq] No, the "deceit" and "flattery" uses are separate. The modern term sycophancy, involving servile or abject flattery, need not involve deceit. The slightly older use of the word (related to Latin sycophantia and Greek sykophantia) refers to the practice of an informer, particularly slanderous or malicious reporting, which need not be flattering at all, but often involves deceit.
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