1 silly

2 stupid

1 great intelligence may appear to be stupidity (idiom)

1 stupid person

2 ignoramus

1 April Fools' Day

1 to make a fool out of

2 to fool

3 to dupe

1 a great hero may appear timid, the wise may appear stupid (idiom); the general public may not recognize great talent

1 the wise may appear stupid (idiom); a genius not appreciated in his own time

1 great intelligence may appear to be stupidity (idiom)

1 the old man moves mountains (idiom); fig. where there's a will, there's a way

1 stupid and ignorant (idiom)