Pretext, n.
Etymology: [F. prétexte, L. praetextum, fr. praetextus, p. p. of praetexere to weave before, allege as an excuse; prae before + texere to weave. See Text.]
Ostensible reason or motive assigned or assumed as a color or cover for the real reason or motive; pretense; disguise. They suck the blood of those they depend on, under a pretext of service and kindness. L'Estrange. With how much or how little pretext of reason. Dr. H. More.
Syn. -- Pretense; excuse; semblance; disguise; appearance. See Pretense.
Shades of meaning
Fernald has no entry of its own for pretext; he lists it under pretense.
Where he writes about it:
A person makes a pretense of something for the credit or advantage to be gained by it; he makes what is allowed or approved a pretext for doing what would be opposed or condemned; a tricky schoolboy makes a pretense of doing an errand which he does not do, or he makes the actual doing of an errand a pretext for playing truant. — from pretense