The most common and most likely answer to this crossword clue is the 6 letter word NORMAL
I've seen this crossword clue in Independent
N
O
R
M
A
L
More clues leading to the result NORMAL
- Customary to see no Royal Marine with a student
- Standard gold kept in New Mexico by gangster
- Typical Indonesian or Malaysian houses
- Neither partner’s masculine — largely typical
- New mark in test achieves standard
- Roman legions, initially battered, showing standard
- Girl student is conventional
- Standard northern exam baffles Mike
- Woman student proved to be average
- Woman wants bit of love primarily – it’s what you’d expect
Buddy explains!

The straight part
We know that "showing standard" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case showing standard = normal.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 NORMAL mean?
NORMAL noun- A line or vector that is perpendicular to another line, surface, or plane.
- A person who is normal, who fits into mainstream society, as opposed to those who live alternative lifestyles.
- The usual state.
- According to norms or rules or to a regular pattern.
- Usual, healthy; not sick or ill or unlike oneself.
- (of a school) teaching teachers how to teach (to certain norms)
- Of, relating to, or being a solution containing one equivalent weight of solute per litre of solution.
- Describing a straight chain isomer of an aliphatic hydrocarbon, or an aliphatic compound in which a substituent is in the 1- position of such a hydrocarbon.
- (of a mode in an oscillating system) In which all parts of an object vibrate at the same frequency (see normal mode).
- (of points) In the default position, set for the most frequently used route.
- Perpendicular to a tangent of a curve or derivative of a surface.