easily understood or performed; straightforward
a simple task
lacking ornamentation; basic or plain
dressed in simple clothes
free from elaboration or showiness; unpretentious
writes in a simple style
free from guile or vanity; innocent or unassuming
lacking experience or sophistication; naive
lacking intelligence; feeble-minded
of humble birth or lowly position
a simple farmer
comprising a single unit; not compound or subdivided
sheer or unqualified
the simple truth
not made up of many like units; not compound, e.g.:
said of a fruit: developing from a single ovary
said of a leaf: not subdivided into branches or leaflets
said of a sentence: consisting of only one main clause and no subordinate clauses
in chemistry, composed essentially of one basic substance or element; fundamental
said of a statistical hypothesis: specifying exact values for the stated statistical conditions