Valmiki Ramayana Aranya Kanda Sarga 60 Shloka 8

भिरुः timid, हृता abducted, मृता वा or dead, नष्टा वा or ruined, भक्षिता वा or eaten up, भविष्यति may be, अथवा or else, निलीना hiding, अथवा or else, वनम् forest, आश्रिता taken shelter,

'Timid Sita might have been abducted or dead or crushed or eaten up by demons. Or, she may be hiding for protection in the forest'