effectual (adj.)

• able
• active
• actual
• adequate
• ascertained
• attested
• authenticated
• authoritative
• banausic
• binding
• capable
• causal
• causative
• certain
• certified
• charismatic
• charming
• competent
• conclusive
• confirmed
• consequential
• constitutive
• corroborated
• decisive
• demonstrated
• determinative
• determined
• documentary
• effective
• efficacious
• efficient
• enchanting
• established
• estimable
• etiological
• factual
• feasible
• forceful
• forcible
• formative
• functional
• go
• historical
• important
• influential
• lawful
• legal
• magnetic
• momentous
• occasional
• operable
• operational
• operative
• originative
• personable
• persuasive
• pivotal
• potent
• powerful
• practicable
• practical
• pragmatic
• prestigious
• productive
• proficient
• proved
• real
• realizable
• reputable
• sound
• strong
• suasive
• substantial
• substantiated
• sure-enough
• telling
• toothy
• true
• truthful
• unquestionable
• useful
• valid
• validated
• veracious
• verified
• veritable
• weighty
• winning
• workable