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alert – v. to give (someone) important information about a possible problem, danger, etc.; to warn (someone)
facial recognition – n. the ability to recognize different faces
vibrate – v. to move a device back and forth or from side to side with very short, quick movements
adjustment – n. a small change that improves something or makes it work better
flat – n. (Chiefly British, European) an apartment typically on one floor
app – n. abbreviation for “application,” a computer program that performs a particular task (such as word processing)
forbidden – adj. not permitted or allowed
frozen – adj. to become unable to do or say anything
stupefy – v. to shock or surprise (someone) very much; to cause (someone) to become confused or unable to think clearly
intruder – n. a person who enters a place illegally
