WordNet sense 1 (the sound made by a gentle blow):

rap, tap

WordNet sense 2 (having only superficial plausibility):

glib, slick

WordNet sense 3 (apparently reasonable and valid, and truthful):

plausible

WordNet sense 4 (pat or squeeze fondly or playfully, especially under the chin):

chuck

WordNet sense 5 (hit lightly):

dab

WordNet sense 6 (suitable for a particular person or place or condition etc):

appropriate, appropriate