Try this:
1. Draw an oval around the word (hold the shift key as you draw if you want
a circle)
2. Right click shape -> format autoshape
3. Change fill to 'no fill' and line colour/style/weight to whatever you
want
4. Right click shape -> custom animation
5. Add Effect -> Entrance -> More Effects -> Wheel (in 'basic' set) -> ok
6. In custom animation taskpane, change Spokes to 1 and change speed/start
to whatever you want.
7. Smile with satisfaction at a job well done.
If any of that isn't clear, let us know and be sure to tell us your version
If you know where you want the circle to appear in advance:
Add an oval and set the fill to none in the correct place, animate using
entrance > Wheel > set to one spoke