Usually used in Jamaican society to insult another being. Similar to the word bombaclaat it has a offensive meaning to deter conflict between two individuals.
The closest english translation would be bastardhole or shit features.
What the rasclaat is this pigeon doing in my room?
A wha dis likkle midgit doing with his rasclaat circus?
Who dem bare feelings dem a carry, u wan test mi food. So mi say again, WELL DUN, you rasclaat
Jamaican swear word. Noun. Comparable to "bastard hole", Shit features, arse-cloth. Rass being "arse" and claat(or klaat) being "cloth".An insulting term for a person,also related to menstruation.