To insert something.
To add an inset to something.
To set in; infix or implant.
A small piece of material used to strengthen a garment.
A smaller thing set into a larger thing, such as a small picture inside a larger one.
Anything inserted.
To include (e.g. a certain word or phrase) into a sentence discreetly
To enter discreetly
To play a subtle pass into someone in a goalscoring position.