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Webster 1913 Edition

Adj.

[L.

proficuus

Profitable; advantageous; useful.

[Obs.]

Harvey.

Adj.

[L. proficuus, proficio, supra.]

Profitable; advantageous; useful. [Little used.]

proficuous ‎(comparative more proficuous, superlative most proficuous)

Useful or profitable.
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