crux Synonyms

Southern Cross quiddity tickler topic why laboriousness bedrock fundamentals puzzler cornerstone alpha and omega crux of the matter thrust tau sum quintessence rebus rood root roun rubicon soul sphinx stumper substance chi jigsaw puzzle moment of truth nuts and bolts Central Point zero hour papal cross pons asinorum main point Crux Australis heart of the matter decisive point brain-teaser point of no return bottom line heart and soul nitty-gritty turning point critical point meat and potatoes be all and end all Gordian knot koan operoseness leaf node