To lose sight of one's companions or to stray away from a group; used often for getting separated in crowds or while traveling.
祭りで人混みに紛れて子供がはぐれてしまった。
In the festival crowd, a child got separated from (his/her) group.
登山のとき、足を滑らせて仲間とはぐれた。
While climbing, I slipped and got separated from my companions.
ツアー中にはぐれないように、ガイドの後ろに付いて行った。
I followed behind the guide so I wouldn't get separated during the tour.
As an auxiliary (often as 〜しっぱぐれる) meaning to miss the chance to do something or fail to do it successfully.
忙しくて彼に謝りっぱぐれてしまった。
I was busy and missed the chance to apologize to him.
申し込みを出しっぱぐれると、参加できない場合がある。
If you miss submitting the application, you might not be able to participate.