Geiger counter Wilson chamber X-ray spectrograph X-ray spectrometer abjure adversary adversative adverse adversive advocate against the grain against the tide against the wind agree to disagree alien allege in support alpha pulse analyzer ambo answer antagonistic antagonize anti antipathetic antipodal antipode antipodean antipodes antipole antithesis antithetic antithetical antonym antonymous argue for ascender assert assert the contrary at cross-purposes at daggers at daggers drawn at issue at odds at opposite extremes at variance at war with athwart atom counter atom-tagger back back to back backward baffle baggage check balancing balk bar bastard type be antipathetic be at cross-purposes be inimical be opposed to beard beat against beat off belie belly bench bevel black letter blast block board body boomerang boron counter brave break break off buffet cap capital case challenge champion check checkmate chip circumvent clash clashing cloud chamber collide come back at comeback compensating competitive con conflict conflict with conflicting confound confront confronting confute contend for contest contra contradict contradictory contradistinct contrapose contrapositive contrarious contrariwise contrary contrast with contrasted contrasting contravene controvert converse cosmic ray counter counteract counteractive counterattack counterbalance counterbalancing counterblast counterblow countercheck countermand counterpoint counterpoise counterpoised counterpole counterpose counterstroke counterterm countervail countervailing counterwork counting tube coupon cross dash dead against defeat defend defy deny descender desk destroy detrimental differ different difficult disaccord disaccordant disaffirm disagree disallow disavow disc disclaim discomfit disconcert discordant discountenance discrepant dish disown disparate disprove dispute disrupt dissent dissentient dissimilar divergent diverse drive back electronic counter elude em en enemy escritoire espouse exchange expansion chamber eyeball to eyeball eyeball-to-eyeball face face to face fantail fat-faced type feet fend fend off flummox foil font forswear fractious frustrate gainsay gamma ray counter get back at give and take give in exchange give in return give-and-take go against go counter to groove hard hardly like harmful hat check heavy particle counter heel hinder hindering hit back at hold at bay hold off hostile impeding impugn in confrontation in hostile array in opposition inconsistent inimical interchange interfere with inverse ion counter ionization chamber ionizing event italic jangle jar join issue upon join the opposition jostle just opposite juxtapose in opposition keep at bay keep off knock the chocks lectern letter