The Collaborative International Dictionary of English v.0.48:

Strictly \Strict"ly\, adv.
   In a strict manner; closely; precisely.
   [1913 Webster]

WordNet (r) 3.0 (2006):

strictly
    adv 1: restricted to something; "we talked strictly business"
           [syn: strictly, purely]
    2: in a stringent manner; "the laws are stringently enforced";
       "stringently controlled" [syn: strictly, stringently]
    3: in a rigorous manner; "he had been trained rigorously by the
       monks" [syn: rigorously, strictly]

Moby Thesaurus II by Grady Ward, 1.0:

56 Moby Thesaurus words for "strictly":
   absolutely, accurately, austerely, conscientiously, dead,
   definitely, directly, even, exactingly, exactly, expressly,
   exquisitely, faithfully, fussily, grimly, harshly, in all respects,
   in detail, in every respect, ipsissimis verbis, just, literally,
   literatim, meticulously, minutely, nicely, plumb, point-blank,
   positively, precisely, punctiliously, punctually, refinedly, right,
   rigidly, rigorously, ruggedly, scrupulously, severely, square,
   squarely, sternly, straight, stringently, to the letter, toughly,
   undeviatingly, unerringly, verbally, verbatim,
   verbatim et litteratim, with exactitude, with great nicety,
   with precision, word by word, word for word