Being very harsh, like ruler overwhelmed by shame (8)
I believe the answer is:
asperity
'being very harsh' is the definition.
I can't tell whether this definition defines the answer.
'like ruler overwhelmed by shame' is the wordplay.
'like' becomes 'as'.
'ruler' becomes 'ER' (abbreviation for Elizabeth Regina).
'overwhelmed by' is an insertion indicator (inserted letters get absorbed or overwhelmed).
'shame' becomes 'pity' (synonyms).
'er' going within 'pity' is 'perity'.
'as'+'perity'='ASPERITY'
Can you help me to learn more?
(Other definitions for asperity that I've seen before include "Roughness, bitterness" , "rough manner" , "Roughness, harshness or coldness" , "'Sharpness, harshness (8)'" , "Harshness, bitter coldness" .)