irreducible (adj) – not able to be reduced, lessened, or simplified
BREAKDOWN: IR- (not) + RE- (back) + DUC- (lead) + -IBLE (able to be)
— reductive means distilling something down to its most basic form or terms
This word is built on the root DUC-, which means to lead.
Common DUC- words include conduct, deduct, duct, educate, introduce, produce, reduce, reproduce, and seduce.
More esoteric DUC- words include adduce and circumduction.