The Form You Would Look For If You Were Looking The Word Up In A ...

Look up can both be transitive and intransitive but its being transitive or not changes the meaning.

look up,ıntransitive,to get better: Things are looking up since her coming as a surgeon to our hospital.

look sb up, transitive, to visit someone: I am planning to look my grandmother up in the afternoon.

look something up, transitive,to find information in a book on a computer etc.Don't ask me!!!Look that word up in your dictionary.

Unfortunately, there is usually no indicator whether an idiomatic phrase is
separable or inseparable. In most cases the phrases must simply
be memorized.

Some two-part verbs are separable, some are not.
If a two-part verb is separable (as 'look up' is separable in your sentence), then you can say either 'look the word up' OR 'look up the word'.
However, when you use a pronoun with a separable two-part verb, then you must separate the verb. So, if you replace 'word' with 'it' in your sentence, then 'it' must be between the two parts of the verb:
look the word up --> OK
look it up --> OK
look up the word --> OK
look up it --> WRONG

Here is a link with a list of separable, inseparable and intransitive two-part verbs:
http://owl.english.purdue.edu/handouts/esl/eslphrasal.html

Isn't look up a phrasal verb?

If it is even then Bokeh is wrong because he is calling look up an idiomatic phrase. This is not an idiomatic phrase.

Hi Jackson

Phrasal verbs can also consist of more than two words. For example, look forward to and look down on
These are not separable.

But you agree that look up is phrasal verb and also that it is not an idiomatic phrase. Right?

BTW here is another sentence which uses separable two-part verb:

When you set the adjective clauses off with commas, you are indicating that the clause is not essential to identify the word it modifies.

Jackson, the word 'idiomatic' is used in many different ways and the word 'phrasal' comes from the word 'phrase'. Basically all phrasal verbs can also be called idiomatic. I also called them something different here, too -- I chose to call them 'two-word verbs' because I only wanted to talk about verbs consisting of exactly two words.

YankeeJackson, the word 'idiomatic' is used in many different ways and the word 'phrasal' comes from the word 'phrase'. Basically all phrasal verbs can also be called idiomatic. I also called them something different here, too -- I chose to call them 'two-word verbs' because I only wanted to talk about verbs consisting of exactly two words.

Idioms are phrases and sentences that do not mean exactly what they say. Even if you know the meaning of every word in the see or hear, you may not understand the idiom because you don't understand the culture behind it. Likewise, idiomatic phrases are obscure phrases whose meaning cannot simply be understood by looking at the words which make them up.

Therefore, I agree that every idiom is a phrase but not every phrase is an idiom. I don't think that all phrasal verbs can also be called idiomatic.