When something rattles or when you rattle it, it makes short sharp knocking sounds because it is being shaken or it keeps hitting against something hard.
1. a rapid series of short loud sounds (as might be heard with a stethoscope in some types of respiratory disorders);
"the death rattle"
Adjective
1. extraordinarily good; used especially as intensifiers;
"a fantastic trip to the Orient""the film was fantastic!""a howling success""a marvelous collection of rare books""had a rattling conversation about politics""a tremendous achievement"
2. quick and energetic;
"a brisk walk in the park""a lively gait""a merry chase""traveling at a rattling rate""a snappy pace""a spanking breeze"
Adverb
1. used as intensifiers; `real' is sometimes used informally for `really'; `rattling' is informal;
"she was very gifted""he played very well""a really enjoyable evening""I'm real sorry about it""a rattling good yarn"