The most common and most likely answer to this crossword clue is the 8 letter word DRAFTING
I've seen this crossword clue in The Guardian
D
R
A
F
T
I
N
G
Buddy explains!
The straight part
We know that "Outlining" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case outlining = drafting.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does DRAFTING mean?
DRAFTING verb- To write a first version, make a preliminary sketch.
- To draw in outline; to make a draught, sketch, or plan of, as in architectural and mechanical drawing.
- To write a law.
- To conscript a person, force a person to serve in some capacity, especially in the military.
- To select someone (or something) for a particular role or purpose.
- To select and separate an animal or animals from a group.
- To select a rookie player onto a professional sports team.
- To follow very closely (behind another vehicle), thereby providing an aerodynamic advantage to both lead and follower and conserving energy or increasing speed.
- To draw out; to call forth.
- To draw fibers out of a clump, for spinning in the production of yarn.
- The act or process of producing a technical drawing, or draft.
- A profession, usually related to making technical drawings for architecture, engineering, or manufacturing.
- The practice among ground vehicle drivers or cyclists of following in a close line to reduce wind resistance.
- A method of preparing fibers for weaving.