IPA: //ˈpoʊstˌtæks//
KK: /ˈpoʊstˌtæks/
Referring to the amount remaining after taxes have been deducted from income or profits.
The posttax income is what you actually take home after all deductions.
Posttax → It is formed from "post-" (meaning after) and "tax" (from Latin "taxare", meaning to assess or estimate). The word "posttax" refers to something that occurs or is calculated after taxes have been applied.
Think of 'after' ('post-') the 'assessment' ('tax') — that's why posttax means what happens after taxes.
No commonly confused words.