Adjective
non-rhotic (not comparable)
Of an accent, most often one of English: not pronouncing the written letter "r" unless it is followed by a vowel, as in received pronunciation, the Boston accent, traditional NYC English, many accents of southern Louisiana, Australian English, etc.
In a non-rhotic accent, the word 'sort' can be pronounced like the word 'sought'.
For example, in non-rhotic dialects of English the "r" in words like "clear" /ˈklɪə/ is usually only pronounced when the following word has a vowel as its first letter (e.g. "clear out" is realized as /ˌklɪəɾˈʌʊt/ ). Source: Internet
Lexical words are somewhat rarer in English and are generally restricted to a single syllable: eye, awe, owe, and in non-rhotic accents air, ore, err. Source: Internet
The phenomenon is comparable to the r in German or in non-rhotic pronunciations of English. Source: Internet