Mainly like a bull but sheepish (5)

I believe the answer is:

ovine

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'sheepish' is the definition.
(I've seen this before)

I don't understand the remainder of the clue.

(Other definitions for ovine that I've seen before include "Like a sheep" , "1/6 = 2/3 of 28 [SHEEPISH" , "Resembling a sheep" , "Pertaining to sheep" , "like a mug" .)

I've seen this clue in the Sydney Morning Herald.

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