coat or mark (something) messily or carelessly with a greasy or sticky substance

his face was smeared with dirt

damage the reputation of (someone) by false accusations; slander

someone was trying to smear her by faking letters

a mark or streak of a greasy or sticky substance

there was an oil smear on his jacket

a sample of tissue or other material taken from part of the body, spread thinly on a microscope slide for examination, typically for medical diagnosis

the smears were stained for cryptosporidium

a false accusation intended to damage someone's reputation

the popular press were indulging in unwarranted smears

an insecure foothold

soon you're eyeballing the top, just one smear away