knock out v.
1. (also bang out) in intransitive uses.
(a) [mid-19C+] to do roughly or quickly, esp. of writing, to create, to make etc.
(b) [late 19C+] (orig. Aus.) to earn a sum of money; e.g. knock out £200 per week; although orig. of food, in phr. knock out tucker.
(c) [late 19C+] to obtain for oneself, e.g. knock out some sleep.
(d) [20C+] to sell.
2. in transitive uses.
(a) [late 19C] to make someone bankrupt.
(b) [late 19C] to fail an examination candidate.
(c) [late 19C–1960s] (US) to deprive someone, esp. of money.
(d) [late 19C+] to kill someone; thus knock-out man n.
(e) [late 19C+] (orig. US) to surprise, overcome or defeat.
(f) [late 19C+] (esp. US black, also knock flat) to impress, to overwhelm, to delight.
(g) [1900s] (Aus.) in fig. use, to surpass.
(h) [1920s–40s] (US Und.) to arrest.
(i) [1940s–70s] to steal, esp. to steal everything from the place one is robbing.
1. to have a very enjoyable time, to ‘let oneself go’, to amaze oneself.
2. to work very hard.
3. to worry.
[1940s+] (US) have a good time!
SE in slang uses
[late 19C+] (US) to defeat, to overcome, to kill.
[mid-18C] to be very drunk.