Words That Rhyme With "Doubtful" :

2 syllables:

crateful, fateful, fitful, fretful, frightful, fruitful, grateful, hateful, hatful, outfall, plateful, potful, rightful, snootful, spiteful, sprightful, thoughtful

3 syllables:

deceitful, delightful, despiteful, forethoughtful, forgetful, regretful, unfruitful, ungrateful, unthoughtful