class_type - informal
Most entries in the SPECIALIST lexicon have been sourced from written work, so they are primarily used in formal (academic or published) contexts. The class_type=informal variants are those lexical items which are used instead in primarily informal contexts. That is, they may be generally seen only in spoken language, or in personal notes or shorthand rather than in published documents. Colloquial terms like those seen in internet forum posts, online chats or text messaging are also included in class_type=informal. Often these variants will be shortened versions of more standard/formal variants ("u" as a variant of "you"; "pls" as a variant of "please", "Xmas" as a variant of "Christmas") but this is not always the case.
Informal tags come with synonym information; the syntax is as follows:
class_type=informal|arg1|arg2|arg3. Arg2 and arg3 are the cross-referenced formal expression synonyms. These synonyms are unidirectional synonyms and must have same part of speech. Unidirectional means that the formal equivalent may be a superset of the informal one. For example, "nite" is an informal variant (and a spelling variant) in the entry for "night", so it is tagged as an informal expression as a synonym of itself. If an informal term has multiple distinct senses, this information will be given by multiple class_type tags.