The difference between Lallygag and Stand by

When used as verbs, lallygag means (see lollygag.) to dawdle, whereas stand by means to wait in expectation of some event.

Lallygag is also noun with the meaning: horseplay, fooling around.

check bellow for the other definitions of Lallygag and Stand by

Lallygag as a verb:

(See lollygag.) To dawdle; to be lazy or idle; to avoid necessary work or effort.
Lallygag as a verb (archaic, US):

To pet, kiss, or otherwise demonstrate overt affection, generally in public.

Stand by as a verb (idiomatic, intransitive):

To wait in expectation of some event; to make ready.

Examples:

"Please stand by for more instructions."
Stand by as a verb (idiomatic, transitive):

To remain loyal or faithful to.

Examples:

"Even though money is scarce sometimes, Ann stands by her decision to be a full-time mother."
Stand by as a verb (idiomatic, transitive):

To support; to continue to support despite things being bad.

Examples:

"They stood by us all along and it's awesome to see them out here to support us today."
Stand by as a verb (intransitive):

To do nothing. To be inactive in a situation.

Examples:

"I can't simply stand by and watch you ruin your life."
Stand by as a verb (intransitive):

to be ready to provide assistance if required.

Examples:

"The tug stood by in case it was needed."