In plain words
Tell me who You are in this terrible form. Salutations to You, supreme Deity; be gracious. I wish to know You, the primal One, for I do not understand Your activity.
Word for word
Tell me who You [are], of fierce form; salutation be to You, O best of gods; be gracious; I wish to know You, the primal one, for I do not understand Your doing.
आख्याहि मे को भवानुग्ररूपोनमोऽस्तु ते देववर प्रसीदविज्ञातुमिच्छामि भवन्तमाद्यंन हि प्रजानामि तव प्रवृत्तिम्
Other commentaries
The commentators
▸Bhagavadgītābhāṣyam
यतः एवमुग्रस्वभावः, अतः —
आख्याहि कथय मे मह्यं कः भवान् उग्ररूपः क्रूराकारः, नमः अस्तु ते तुभ्यं हे देववर देवानां प्रधान, प्रसीद प्रसादं कुरु । विज्ञातुं विशेषेण ज्ञातुम् इच्छामि भवन्तम् आद्यम् आदौ भवम् आद्यम् , न हि यस्मात् प्रजानामि तव त्वदीयां प्रवृत्तिं चेष्टाम् ॥ ३१ ॥
In plain words
Because you have shown yourself to be this fierce — that is why —
Tell me — who are you, appearing in this fierce, terrible form? I bow to you all the same. O greatest of the gods, chief among them all, be gracious to me. I want to understand you fully, you who were there at the very beginning — because, truly, I have no idea what you are doing, or why.
Close to the Sanskrit
Because you are of such fierce nature, therefore —
Tell me, say to me, who are you, of fierce form, of cruel appearance? Salutation be to you, O best of gods, chief among the gods; be gracious, show grace. I wish to know specially, to understand, you, the primal one — existing at the beginning, the primal one — for indeed I do not know your, your own, activity, conduct.