This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

adj. Of, pertaining to, or featuring interaction

Pertaining to or of the nature of interaction.

adj. capable of acting on or influencing each other

"Sometimes they cross their legs, put their hands on their laps, scratch their heads, and so forth in what has been termed interactional synchrony."

interacted    interacting    interactional    interactively    interacts   

act    move   

relate    do by    handle    connect    have    patronise    foregather    socialize    womanise    intercommunicate   

interlude    interplay    engage    mesh    reciprocate   

abstract    act    attacked    attract    backed    blacked    compact    contract    counterattacked    cracked   

submicron    ribosome-inactivating    monodisperse    smoaky    igniting    hadronic    superluminal    submicroscopic    vidrion    nucleosome