Sentence:  It is the one exercise that drastically influences the definition of the thighs at the hipline - that mark of the champion that sets him apart from all other bodybuilders - a criterion of muscle `` drama '' that is <WSD>unforgettable</WSD> to judges and audiences alike - the facet of muscular development that wins prizes . 
Meaning of the word marked with <WSD> tags:  impossible to forget