To take (someone) into one's confidence, to speak in secret with. ( + in)
To say (something) in confidence.
To formally give (someone) some power or authority.
To surround, accompany, or attend.
To spend money, time, or energy on something, especially for some benefit or purpose; used with in.
To commit money or capital in the hope of financial gain.
To ceremonially install someone in some office.
To lay siege to.
To be involved in; to form strong attachments to.
To prepare for lost wax casting by creating an investment mold (a mixture of a silica sand and plaster).
To make investments.
To envelop, wrap, cover.
To formally give (power or authority).
An unnamed tropical weather pattern "to investigate" for development into a significant (named) system.