Comparative law notes
a proffer is an offer made prior to any formal negotiations. In a trial, to proffer (sometimes profer) is to offer evidence in support of an argument, or elements of an affirmative defense or offense. A party with the burden of proof must proffer sufficient evidence to carry that burden.
In context of pleadings or civil/criminal proceedings, we would suggest
using the phrase "proffer of evidence" only because the term "proffer",
standing alone, may not resonate with many non-native English-speaking
lawyers.