Thickener helping you finally blot a pen (3,6)
I believe the answer is:
gum arabic
'thickener' is the definition.
Both the definition and answer are singular nouns.
Maybe you can see a link between them that I don't see?
'helping you finally blot a pen' is the wordplay.
'finally' says to take the final letters.
'blot' becomes 'mar' (I've seen this in another clue).
'pen' becomes 'bic' (pen manufacturer).
The final letters of 'helping you' are 'gu'.
'gu'+'mar'+'a'+'bic'='GUM ARABIC'
Can you help me to learn more?
(Other definitions for gum arabic that I've seen before include "Ingredient of 16 across" , "Exudation used in glues and incense" , "glue" , "Substance exuded by acacia" .)