This was the word that first caught my eye as the obverse of onomatopoeia.
( This ( ( was ( ( the word ) ( that ( first ( ( caught ( my eye ) ) ( as ( ( the obverse ) ( of onomatopoeia ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT This)) (VP (VBD was) (NP (NP (DT the) (NN word)) (SBAR (WHNP (WDT that)) (S (ADVP (RB first)) (VP (VBD caught) (NP (PRP$ my) (NN eye)) (PP (IN as) (NP (NP (DT the) (NN obverse)) (PP (IN of) (NP (NN onomatopoeia)))))))))) (. .)))
My attention was caught by a certain word. 
( ( My attention ) ( ( was ( caught ( by ( a ( certain word ) ) ) ) ) . ) )
(ROOT (S (NP (PRP$ My) (NN attention)) (VP (VBD was) (VP (VBN caught) (PP (IN by) (NP (DT a) (JJ certain) (NN word))))) (. .)))