Is it permissible to pray Dhuhr and Asr bowing (ruku') when unable to pray standing (qiyam) for fear of being seen by men?

Standing during prayer is a pillar that is not waived except in cases of inability. A woman being seen by non-mahram men while she is praying is not an excuse to abandon standing. It is more prudent to repeat the prayers that were performed sitting due to this excuse.