"being full to the brim," 1660s, present-participle adjective from brim (v.).
Entries linking to brimming
brim v.
"to fill to the brim," 1610s, from brim (n.). The intransitive sense of "be full to the brim" is attested from 1818. To brim over "overflow" is from 1825. Related: Brimmed; brimming.