Slip-by meaning

She tried to slip by quietly, but he glanced up as she passed.

Was Edith's vivid imagination working overtime or had Jerome Shipton managed to slip by Janet O'Brien and invade his wife's room?

I can see how that might slip by you, but how could you miss hearing about him on the news?

The opportunity was allowed to slip by.

This latest war of the words, perhaps just a slip by Lohan, again puts the hot topic of Hollywood friendships in the spotlight.