A.T. Robertson Commentary Luke 24:37

"But they were terrified and affrighted, and supposed that they beheld a spirit." — Luke 24:37 (ASV)

Terrified (πτοηθεντες). First aorist passive participle of πτοεω, old verb and in the N.T. only here and Lu 21:9 which see.

Affrighted (εμφοβο γενομενο). Late adjective from εν and φοβος (fear). Both these terms of fear are strong.

Supposed (εδοκουν). Imperfect active of δοκεω, kept on thinking so.