chemistry
interpersonal chemistry
alchemy
personal relationship
personal relation
similitude
parasitism
connection
term
mind meld
corelation
duo
duet
couple
divide
affinity
twosome
relation
likeness
sociation
alikeness
Tweedledum and Tweedledee
Tweedledee and Tweedledum
interrelationship
tie
reciprocity
one-to-one
interreference
hermaphrodite
metarelation
betweenity
co-vilification
personality clash
dyad
cognation
interplay
distinction
double switch
coincider
referrer
beauty and the beast
relationship
one and the same
comparate
correlation
two sides of the same coin
correlativity
crosslinkage
vis-à-vis
BroTP