Is it long term or long-term?
Both forms exist; the difference between them (ie the use of the hyphen) is very important and applies to many other elements across English.
When talking about the ‘long term’, we are talking about the noun ‘term’. We are then further describing that by using the adjective ‘long’. See (1) below.
However, where the entire phrase is used to describe something else, we must use the hyphen to show this. This is called a premodifying compound adjective. See (2) below.
- We are planning for the long term.
- This is a long-term plan.