Argue irrationally, having a screwy point (5)
I believe the answer is:
auger
'a screwy point' is the definition.
'auger' can be an answer for 'point' (thesaurus). I am unsure of the 'a screwy' bit.
'argue irrationally' is the wordplay.
'irrationally' indicates an anagram.
'argue' anagrammed gives 'AUGER'.
'having' acts as a link.
Can you help me to learn more?
(Other definitions for auger that I've seen before include "Tool for boring holes in wood" , "A tool for boring hole in wood" , "Boring-tool" , "I bore" , "Boring instrument" .)