have a sneaking feeling/suspicion/admiration
From Longman Dictionary of Contemporary Englishhave a sneaking feeling/suspicion/admirationhave a sneaking feeling/suspicion/admirationSUSPECTto have a feeling about something or someone, but to not say anything about it because you are not sure or you might be embarrassed I always had a sneaking admiration for him. She had a sneaking suspicion that he was lying. → sneaking