Wiktionary:Idioms

Set phrases are, in the strictest definition, phrases that are invariant, that is, no change whatsoever is possible in the phrase. Relaxing the conditions to broaden the definition allows many more candidates:

1. A constituent may inflect (plural/singular, tense)

   *kick the buckets

   kicking the bucket

   kicks the bucket

   kicked the bucket

2. A verb constituent may accept negation and be used with auxiliaries.

   did kick the bucket

3. The constituents may be modified individually by adjuncts, especially adjectives and adverbs, at least those that appear outside the candidate set phrase itself.

   *kick the milk bucket

   *kick theatrically the bucket

   theatrically kick the bucket

4. A noun constituent may accept alteration of determiners and articles.

   *kick [__] bucket

   *kick a bucket

   *kick this bucket

Almost all reasonable definitions of "set phrase" allow for inflection. The appearance of modifiers within the phrase structure is usually fatal to an item being a set phrase. Sometimes no modification of the determiners can occur.

Thus, one of the principal tests for excluding a term as a set phrase is thus the appearance of adjuncts within the candidate phrase.

Another test is the coordination test. Can a coordination be substituted for the component words?

*kick and damage the bucket

*damage and kick the bucket

*kick the bucket and the dog

Any coordination will do, but the appear of "and" or "or" before or after the candidate phrase is the most convenient way of searching for such a phrase.

• Most of the time, you should use “one” or “one’s”, not “his” or “your”, though for phrases that only exist in one form specific words should be used.
• Most of the time you should use a bare verb form, as would be found in a dictionary scrimp and save, not to scrimp and save, though sometimes you will find idioms that only exist in one form of the verb.

For the part of speech (POS), use {{head|xx|phrase|head=…}}, which correctly formats it and categorizes it as a phrase, and allows you to link the individual words or subphrases.

To mark an entry or a definition as idiomatic, use {{lb|xx|idiomatic}}, which automatically inserts the proper text and category.

• {{head|xx|phrase|head=…}}

You can link individual words or components using {{head}} with the |head= argument – best is to link subphrases, if possible, rather than just the individual words.

For foreign languages, you may find {{l}} helpful – see discussion.

• {{label|xx|idiom}}

Use to flag idioms at the start of the definition.

• {{alternative form of|…}}

Use when there are several wordings for a given idiom, though it may be appropriate to use a redirect in some very similar cases, such as inflections and pronouns: burn his fingers and burning one's fingers should redirect to the pronoun-neutral and uninflected form burn one's fingers.
See WT:REDIR#Redirecting between different forms of idioms.

As per Wiktionary:Translations,

• Do not give literal (word-for-word) translations of idioms, unless the literal translation is actually used in the target language. Most idioms do not translate word for word.

• Category:English idioms
• Some thesaurus considerations apply to idiom dictionary use.
• Idiom dictionary article in Wikipedia
• Wiktionary:Wiktionary idiom dictionary considerations (inactive as of this writing)
• Wiktionary:Idioms that survived RFD