grope after (someone or something)
To try, often unsuccessfully, to touch, catch, or grasp someone or something. I groped after Sally's hand as the car came careening down the street. Tanya groped after the string, but it slipped away, and the balloon floated toward the sky.
grope after someone or something
to reach for a departing or fleeing person or thing awkwardly or ineffectually. The feeble hand groped after the departing form. I groped after the cat as it ran under the bed.