Bogart almost upset female star (5)
I believe the answer is:
garbo
'female star' is the definition.
The definition suggests a singular noun which matches the answer.
'bogart almost upset' is the wordplay.
'almost' means to remove the last letter (most of the word but not all of it).
'upset' is an anagram indicator.
'bogart' with its final letter taken off is 'bogar'.
'bogar' is an anagram of 'GARBO'.
Can you help me to learn more?
(Other definitions for garbo that I've seen before include "Greta . . . . ., film star who wanted to be alone" , "Famous film actress" , "Old film actress" , "Swedish-born actress" , "Swedish actress who wanted to be alone" .)