trifle, toy, dally, flirt, coquet mean to deal with or act toward without serious purpose.

trifle may imply playfulness, unconcern, indulgent contempt.

toy implies acting without full attention or serious exertion of one's powers.

dally suggests indulging in thoughts or plans merely as an amusement.

flirt implies an interest or attention that soon passes to another object.

coquet implies attracting interest or admiration without serious intention.

delay, procrastinate, lag, loiter, dawdle, dally mean to move or act slowly so as to fall behind.

delay usually implies a putting off of something (such as a beginning or departure).

procrastinate implies blameworthy delay especially through laziness or apathy.

lag implies failure to maintain a speed set by others.

loiter and dawdle imply delay while in progress, especially in walking, but dawdle more clearly suggests an aimless wasting of time.

dally suggests delay through trifling or vacillation when promptness is necessary.