To interpose oneself; to intervene.
To insert something between other things.
To say as an interruption or aside.
To take upon oneself; to start, to embark on (a specific task etc.).
To commit oneself (to an obligation, activity etc.).
To pass a slower moving vehicle on the curbside rather than on the side closest to oncoming traffic.
The passing of slower traffic on the curbside rather than on the side closest to oncoming traffic.