Taṣuddu is an imperfect verb from ṣ-d-d (ص د د), meaning to turn away or avert oneself. Tubdī is a Form IV imperfect from b-d-w (ب د و), meaning to disclose or reveal. Both refer to the same feminine subject and are connected by wāw.
Placing the verbs side by side sets up a tension between seclusion and visibility. The scene is not a motionless front-facing portrait; the poet repeatedly evokes a figure turning aside yet showing a glimpse.
The imperfect tense contributes a sense of an ongoing or renewed quality, rather than a once-for-all completed action.