To contaminate with a disease-causing organism or agent. The virus can infect humans through direct contact with bodily fluids.
To affect or contaminate with a harmful influence or feeling. His enthusiasm began to infect everyone in the team, boosting morale.
To transmit a computer virus to a program or system. The malware was designed to infect computers through email attachments.
To become infected; to develop an infection (intransitive). If left untreated, the wound may infect.