true toad vs toad frog

true toad and toad frog both are nouns.

Word	Noun	Adjective	Verb	Adverb
true toad	Yes	No	No	No
toad frog	Yes	No	No	No

As nouns, toad frog is a hypernym of true toad; that is, toad frog is a word with a broader meaning than true toad:

true toad: tailless amphibian similar to a frog but more terrestrial and having drier warty skin
toad frog: any of various tailless stout-bodied amphibians with long hind limbs for leaping; semiaquatic and terrestrial species

Other hypernyms of true toad include anuran, batrachian, frog, salientian, toad.

true toad (noun)	toad frog (noun)
tailless amphibian similar to a frog but more terrestrial and having drier warty skin	any of various tailless stout-bodied amphibians with long hind limbs for leaping; semiaquatic and terrestrial species