Assent grudgingly means to reluctantly agree or consent to something. Some synonyms for this phrase could include: concede reluctantly, approve begrudgingly, assent unwillingly, comply with reluctance, yield with reservation, agree with hesitation, and give in with reluctance. These terms all express a similar sentiment of agreeing to something but with a sense of reluctance or dissatisfaction. They all convey the idea that the person agreeing is doing so despite their own reservations or objections. Ultimately, each synonym captures a different nuance of the same concept, providing speakers and writers with a range of options to express their ideas in a more precise and nuanced way.