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foil 1

tr.v. foiled, foil·ing, foils
1. To prevent from being successful; thwart: The alarm system foiled the thieves' robbery attempt.
2. To obscure or confuse (a trail or scent) so as to evade pursuers.
n. Archaic
1. A repulse; a setback.
2. The trail or scent of an animal.

[Middle English foilen, to trample, defile, variant of filen, to defile; see file3.]

foil 2

1. Metal that has been formed into a thin, flexible sheet: aluminum foil.
2. A thin layer of polished metal placed under a displayed gem to lend it brilliance.
3. One that stands in contrast to and emphasizes the distinctive characteristics of another: "I am resolved my husband shall not be a rival, but a foil to me" (Charlotte Brontë).
4. The reflective metal coating on the back of a glass mirror.
5. Architecture A curvilinear, often lobelike figure or space formed between the cusps of intersecting arcs, found especially in Gothic tracery and Moorish ornament.
a. An airfoil.
b. Nautical A hydrofoil.
tr.v. foiled, foil·ing, foils
1. To cover or back with foil.
2. To wrap (strands of hair) in pieces of foil in order to isolate them after bleach or color has been applied.
3. To set off by contrast.

[Middle English, from Old French foille, from Latin folia, pl. of folium, leaf; see bhel- in Indo-European roots.]

foil 3

1. A fencing sword having a usually circular guard and a thin, flexible four-sided blade with a button on the tip to prevent injury.
2. often foils The art or sport of fencing with such a sword: a contest at foils.

[Origin unknown.]
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.foiling - an act of hindering someone's plans or efforts
interference, hinderance, hindrance - the act of hindering or obstructing or impeding
References in classic literature ?
Minerva answered, "Would, indeed, this fellow might die in his own land, and fall by the hands of the Achaeans; but my father Jove is mad with spleen, ever foiling me, ever headstrong and unjust.
I obeyed, swimming slowly on, while Otoo swam about me, keeping always between me and the shark, foiling his rushes and encouraging me.
At any rate, I rather doubt that you or I would have chosen a similar plan for foiling an angry and a hungry lion.