This is the 10205th most frequent Japanese word.
間接
Indirect.
Here, '間接的に' (indirectly) is used as an adverb to describe the manner in which the action was performed.
間接的に彼の意見を聞きました。
I indirectly heard his opinion.
'間接的に得た' indicates that the describing of obtaining information was not done directly but via secondary means.
その情報を間接的に得た。
I obtained that information indirectly.
'間接話法' refers to a grammatical term 'reported speech', highlighting a way of expressing someone's words or expressions indirectly.