"They thought it was more trenchant."

Caravaggio is punning on the word trenchant.

trench·ant  (trnchnt)

adj.
1. Forceful, effective, and vigorous: a trenchant argument. See Synonyms at incisive.
2. Caustic; cutting: trenchant criticism.
3. Distinct; clear-cut.

[Middle English, from Old French, cutting, from present participle of trenchier, to cut; see trench.]

trenchan·cy n.
trenchant·ly adv.