1) Adama 2) Adamant 3) Austere 4) Cruel 5) Definite 6) Dyed-in-the-wool 7) Extreme 8) Firm 9) Hardcore 10) Hardline 11) Inflexible 12) Intransigent 13) Persistent 14) Rigid 15) Stern 16) Strict 1) Hard-line 2) Inflexible 3) Intransigent 4) Making no concessions 5) Not making concessions 6) Undeviating 7) Unyielding 
• (a.) Not admitting of compromise; making no truce or concessions; obstinate; unyielding; inflexible.
[adj] - not making concessions
sturdy adjective not making concessions; `took an uncompromising stance in the peace talks`; `uncompromising honesty`
not admitting of compromise or adjustment of differences; making no concessions; inaccessible to flexible bargaining; unyielding: an uncompromising attitude. · without reservation or exception; undeviating; absolute, as believing in or adhering to a principle, position, or the like: an uncompromising abolitionist.