• inderect,
• ineract,
• inneract,
• eneract,
• underate,
• underand,
• enteract,
• ynderact,
• hnderact,
• jnderact,
• 8nderact,
• undefelt,
• underunk,
• unwearyig,
• undeaft,
• undebrace,
• Underkast,
• undecraft,
• Underarest,
• undergrt

• underclass,
• undertide,
• underarm,
• unweathered,
• undergo,
• unutterable,
• underpin,
• undershirt,
• undergird,
• undertow,
• underactive,
• underwrite,
• undersea,
• understood,
• undercut,
• underrating,
• underwear,
• under that,
• unutterably,
• underfur,
• underage,
• underfelt,
• underfed,
• underway,
• undergrowth,
• under wraps,
• underplay,
• underquote,
• understand,
• underwater,
• underrate,
• undershoot,
• undershrub,
• underbid,
• underpay,
• underlay,
• under it,
• underneath,
• understock,
• undertake,
• understudy,
• undershot,
• undercoated,
• underlie,
• underskirt,
• underpart,
• undercover,
• undoer,
• under way,
• underfoot,
• undertaking,
• understated,
• undertaker,
• underseal,
• underworld,
• undertone,
• undrape,
• untier,
• undraped,
• under,
• undersealed,
• undercharge,
• undercoat,
• undergrad,
• undrawn,
• underwriter,
• under arms,
• underframe,
• underpants,
• undramatic,
• understate,
• underdog,
• underspent,
• unmoderated.

The adverb form of "underact" is "underacting".

The adjective form of the word "underact" is "underacted".

The plural form of the word "underact" is "underacts"

The singular form of the word "underact" is "underact". It remains the same in both singular and plural forms.