Flap observed to lie the wrong way (6)

I believe the answer is:

tiswas

I'm a little stuck... Click here to teach me more about this clue!

'flap' is the definition.
I know nothing about this answer so I can't tell whether this works.

'observed to lie the wrong way' is the wordplay.
'observed' becomes 'saw' (seen).
'to lie' becomes 'sit'.
'the wrong way' says the letters should be written backwards.
'saw'+'sit'='sawsit'
'sawsit' written backwards gives 'TISWAS'.

Can you help me to learn more?

(Other definitions for tiswas that I've seen before include "commotion" , "state" .)

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.