Source : WordNet®

head-to-head
     adj 1: involving two persons; intimately private; "a tete-a-tete
            supper"; "a head-to-head conversation" [syn: {tete-a-tete}]
     2: inconclusive as to outcome; close or just even in a race or
        comparison or competition; "as they approached the finish
        line they were neck and neck"; "the election was a nip and
        tuck affair" [syn: {neck and neck}, {nip and tuck}]
     adv : even or close in a race or competition or comparison; "the
           horses ran neck and neck"; "he won nip and tuck" [syn:
           {neck and neck}, {nip and tuck}]