思議 is read as しぎ (shigi) and means conjecture.
しぎ
shigi
ふしぎ
strangely enough
ななふしぎ
seven wonders (of a particular area)
あうもふしぎあわぬもふしぎ
dreams and fortune-telling are hit-and-miss
せかいのななふしぎ
Seven Wonders of the World
ふかしぎ
10^64 (or 10^80)
ふしぎのくにのありす
Alice in Wonderland (novel by Lewis Carroll)
ふしぎくん
eccentric young man
ふしぎがる
to be curious
ふしぎちゃん
eccentric young person (esp. girl)
ふしぎなほど
wondrous
ふしぎなくらい
curiously
ふしぎなえん
quirk of fate