To become involved or associated with (especially a group of people)
To introduce or add (something that is different or foreign).
To introduce (code) into an existing program or its memory space, often without tight integration and sometimes through a security vulnerability.
To take or be administered something by means of injection, especially medicine or drugs.
To introduce (something) suddenly or violently.
To administer an injection to (someone or something), especially of medicine or drugs.
To push or pump (something, especially fluids) into a cavity or passage.