(n.) An ostensible reason or motive assigned as a cover for the real reason\; pretense; disguise.

acting affectation alibi allege alternative appearance attitudinizing avow bluff bluffing camouflage cheating choice claim cloak color coloring cover cover story deception delusion disguise dissemblance dissembling dissimulation escape clause escape hatch excuse explanation facade face fakery faking false air false front false show falsity feigning feint four-flushing fraud front gilt gloss guise humbug humbuggery imposture loophole masquerade meretriciousness ostentation outward show playacting plea pose posing posture pretend pretense pretension profess protest too much purport rational ground rationale rationalization reason reason for reason why red herring representation right ruse saving clause seeming semblance sham show simulacrum simulation speciousness stated cause the big idea the idea the whatfor the wherefore the why underlying reason varnish veil way of escape way out window dressing