#1 slip v. [steal] move stealthily; "The ship slipped away in the darkness". wn
#2 slip v. insert inconspicuously or quickly or quietly; "He slipped some money into the waiter's hand". wn
#3 slip v. [skid, slue, slew, slide] move obliquely or sideways, usually in an uncontrolled manner; "the wheels skidded against the sidewalk". wn
#4 slip n. [faux pas, gaffe, solecism, gaucherie] a socially awkward or tactless act. wn
#5 slip v. [drop off, drop away, fall away] get worse; "My grades are slipping". wn
vizzz