Wiktionary
n. (context chiefly US idiomatic English) A situation or activity in which the participants show a lack of skill, sound judgment, or professionalism.
Wikipedia
"Amateur Hour" is a song by Sparks. It was released as the second single from their 1974 album Kimono My House. Bassist Martin Gordon was requested to replace his original bass part (recorded using a Rickenbacker 4001 bass) with a Fender Precision bass, belonging to his subsequent replacement in the band.
A re-recording was produced in 1997 for the retrospective Plagiarism album. This new version was given a complete electronic synthpop overhaul and was performed with Erasure.
On 25 June 2009 the song "Amateur Hour" was featured in a stunt when UK magician and mentalist Mark Cairns predicted that radio personality George Lamb would choose the Sparks song in a free choice from a list of 100 tracks that had been recently played on Lamb's BBC Radio 6 Music show.
Usage examples of "amateur hour".
Now here's the man you're all waiting forthe star of the famous Amateur Hour and now of our new Happy Hourmy nice boss, Mr.
Even trained soldiers have a hard time against Ghost Warriors, and this city's army is strictly amateur hour.