carry out a systematic or formal inquiry to discover and examine the facts of (an incident, allegation, etc.) so as to establish the truth:police are investigating a claim that the man was beaten unconscious by a gang
carry out research or study into (a subject or problem, typically one in a scientific or academic field): [with clause]:future studies will investigate whether long-term use of the drugs could prevent cancer
make inquiries as to the character, activities, or background of (someone):everyone with a possible interest in your brother’s death must be thoroughly investigated
[no object] make a check to find out something:when you didn’t turn up I thought I’d better come back to investigate
