convincing or believable by virtue of forcible, clear, or incisive presentation; telling.
2.
to the point; relevant; pertinent.
Origin: 1650–60; < Latin cōgent- (stem of cōgēns, present participle of cōgere to drive together, collect, compel), equivalent to cōg- (co-co- + ag-, stem of agere to drive) + -ent--ent
1659, from Fr. cogent "necessary, urgent" (14c.), from L. cogentem (nom. cogens), prp. of cogere "to curdle, to compel, to collect," from com- "together" + agere "to drive" (see act).