button-down

[buht-n-doun] /ˈbʌt nˌdaʊn/
adjective
1.
(of a shirt collar) having buttonholes so it can be buttoned to the body of the shirt.
2.
(of a shirt) having a button-down collar.
3.
(especially of attitudes, opinions, etc.) extremely conventional; unimaginative.
Also, buttoned-down.
Origin
1930-35, Americanism
British Dictionary definitions for button down

button-down

adjective
1.
(of a collar) having points that are fastened to the garment with buttons
2.
(of a shirt) having a button-down collar
3.
Also buttoned-down. conventional or conservative: a button-down corporate culture
Slang definitions & phrases for button down

button down

verb phrase
  1. To classify; peg, pigeonhole: I buttoned him down from the start as a probable bore
  2. To make precise; discard all but one alternative: First we decide to buy, then we button down the price
  3. To prepare for action; get ready: He was all buttoned down and ready to go

[1950s+; third sense fr a military term for closing all ports and hatches for action]