straightforward vs aboveboard

straightforward and aboveboard both are adjectives.

Word	Noun	Adjective	Verb	Adverb
straightforward	No	Yes	No	No
aboveboard	No	Yes	No	Yes

As adjectives, straightforward and aboveboard are synonyms defined as:

straightforward and aboveboard: without concealment or deception; honest

straightforward (adjective)	aboveboard (adjective)
pointed directly ahead	without concealment or deception; honest
without evasion or compromise
without concealment or deception; honest
free from ambiguity

straightforward (adverb)	aboveboard (adverb)
	in an honest manner