Pretext (noun)

A reason or excuse given in pretext for an action or behavior that is not the real reason; a false or fictitious reason.

Origin:

From the latin praetextus (disguise), from prae (before) + textus (text), from texere (to weave). first recorded in english in the early 17th century.

Examples:

1. He used the pretext of needing to work late to avoid spending time with his family.
2. The company used the pretext of cost cutting to justify layoffs.
3. She used the pretext of going to the store to leave the party early.
4. He used the pretext of a headache to avoid going to the meeting.
5. They used the pretext of security reasons to deny entry to the building.