Pull one or two up then lick your fingers. Then wash your hands and then lick your fingers again. If after washing your hands numerous times, you still taste the yuck of the weed, then you will know for sure it’s bitter weed.
I vividly remember picking some of those for my mother back when I was a little fellow. Didn’t think I would ever get my hands clean again.
RoundUp (glyphosate) will set the clover back a bit but won't kill it, in particular if you do it with plenty of moisture in the ground or when the clover is going dormant.